Class Book ~S3Z1 Copyright N^. COPYRIGHT DEPOSnV CONCRETE ROADS AND PAVEMENTS By E. S. HANSON Affiliated Member Western Society of Engineers, Elitor The CEMK.vr Era, Author "Cement Pipe and Tile," etc. CHICAGO The Cement Era Publishing Company 1913 T t XT? Copyright 1913 by The Cement Era Publishing Company. ;3'/9/to / fh-^ >C1.A35417 PREFACE. The essentials of a good roadway are far different at the present time from what thev were a few years ago. The introduction of high-speed vehicles, with tires covering a broad band of road and at the same time having well developed qualities of suction, has made necessary an entire revision of the science of roadmaking. Within the past few years the opinion has rapidly gained ground that the best material to meet these new conditions is concrete. A demand for information on this topic has thus been created, which it is the purpose of this volume to supply. The book is, in large part, frankly a compilation, and the effort has been to collect into convenient hand- book size everything of value which is so far known on the subject. It is hoped that the book will serve not only to stimulate construction of this class of roadways, but will also furnish roadmakers such specific data from the experience of others as to enable them to build the best class of concrete roads and pavements. E. S. Haxsox. Chicago, August 1, 1913. CONTENTS. Page. Chapter I. Concrete as a Road Material 5 II. The Construction of Concrete Roadways... 20 III. The Roads of Wayne County, Michigan 33 IV. Cost of Concrete Roads in Illinois 50 V. Other Examples of Concrete Roads 63 VI. Some Data on City Pavements 82 VII. Reinforced Concrete Pavements 97 VIII. Concrete in Combination with Other Ma- terials 112 IX. Patented Concrete Pavements 125 X. The Theory and Practice of Joints 139 XI. Some Tests on Concrete as a Roadway Material 146 XII. Bridges and Culverts 159 XIII. Sidewalks, Curbs and Gutters 177 Appendix A. Specifications of National Association of Cement Users — Roads and Pavements. . . .179 B. Wayne County Specifications 185 C. Mason City Specifications 194 D. Specifications of Illinois Highway Commis- sion 197 E. Specifications for Blome Granitoid Pave- ment 202 F. Specifications for Blome Granocrete Pave- ment 205 G. Specifications for Bitustone Pavement 208 H. Specifications for Dolarway Pavement 210 I. Specifications for Hassamite 212 J. Specifications for Bridges and Culverts. .. .214 K. Specifications for Sidewalks 218 L. Specifications for Curbs and Gutters 223 Concrete Roads and Pavements CHAPTER I. Concrete as a Road ]\rATKRiAL. It is assiuncd at the outset that the reader is a ])erson siifficieiitlj^ well informed to recognize the value of good roads and pavements, so that it will not be necessarv here to take up any arguments in behalf of the subject as a whole. Such work is much needed, to be sure ; but the one who takes up -, this book will already be a convert to this good roads movement, and will look to these pages, not for enthusiasm in the cause — which he already possesses — but for informa- tion and instruction regarding a type of roadway which has made rapid advancement within the past few years. AVithout further preliminaries, therefore, let us consider the essentials of a good roadway, so that we may see what the standards are by which a road must be measured. We shall then be in a position to apply the test to concrete roads and pavements and see how they measure up to the standard. The most scientific discussion of the qualities of a good roadway which the Avriter has seen is that of ^Er. Geo. W. Tillson, consulting engineer to the President of the Borough of Brooklyn, City of Xew York. This is given in the second edition of Mr. Tillson's volume (5) G Concrete Roads and Pavements. entitled ^^ Street Pavements and Paving Materials." Supposing the perfect pavement to liave a value of 100, Mr. Tillson assigns various percentages to the different qualities, the list being as follows : Cheapness l-t Durability 21 Ease of cleaning 15 Resistance to traffic 15 I^on-slipperiness 7 Ease of maintenance 10 Favorableness to travel 15 Sanitariness l;3 100 This table was prepared primarily with city pave- ments in mind, and would perhaps be subject to some variation for country roads. ^Nevertheless, the writer is inclined to believe that it is just and fair, though he would possibly feel like giving a somewhat higher value to the item of maintenance. The application of this table of values to concrete roadways will show them to have decided advantages on every count. Cheapness. This relates primarily to first cost, leaving out of consideration for the time being any thought whatever of the ultimate, long-time, or real cost. That is, can a given community pay the initial cost of concrete without unduly drawing upon its pres- ent resources or too heavily mortgaging the future ? In answering this question, city pavements and country roads will have to be considered separately, inasmuch as in practically all localities the custom has been to accord the two an entirely different treatment. Concrele Roads and Pavements. 7- giving the city street a durable, well built pavement, while the country road has been content with almost any makeshift it could get. This is a condition which we believe will continue but a few years longer, ex- cept in very sparsely settled districts where the con- struction of permanent roads is out of the question ; but so long as it remains it must be considered in any discussion of this kind. The automobile is accused of many things in connection with street and road prob- lems; but it can at least be credited with this, that it is serving to wipe out the line of demarcation between the city and the country, so that the builder of good roads cannot longer feel that his work is done when he has worked out to the city limits. The time is com- ing when roadways will be considered very largely as a unit, irrespective of municipal boundaries ; but until that time they will have to be treated separately. Taking up first, then, the cost of city pavements, a few comparative figures will serve to show that con- crete is not high in first cost. We give cost data on these pavements in several different places in this vol- ume, but the large table of work done in 1912 will perhaps be sufficiently comprehensive for purposes of comparison, and they are more recent than many others given. In this table, which was compiled by The Cement Era, there are given cost figures for 81 cities; and while these figures were compiled from a number of different statements, representing, perhaps, widely divergent ideas as to what should be included in a cost statement, they are fairly representative, and it is of interest to note that they average a cost of $1.30 per square yard. Figaires compiled by Engineering and 8 Concrete Roads and Pavements. Contracting for 141 cities ave practically the same, or $1.31 per square yard. While some of these statements include grading, many of them do not, as this is highly variable, the cost depending on the nature of the soil and the contour of the ground. They probably in most cases do not include also the item of engineering super- vision and administrative expenses. Some of the work was probably done, too, when cement was very low in price, so that a cost of $1.50 per square j^ard is perhaps as close a total average figure as can be given. And yet, taking all these things into considera- tion, the man who has had experience either in buying or building city pavements will know that this is as low a price as will buy any kind of a pavement accept- able to the general public. In fact, it is below the average price of any other material which any enter- prising city would think of using. It is interesting to compare the price of concrete pavement Avith the price of other classes of pavements as compiled by Engineering and Contracting in the same issue above referred to. In 272 cities reported as laying brick pavement, the average price was $1.82 ; the aver- age price for asphalt block in 14 cities was $2.48 ; for stone block in 46 cities, $2.96; for wood block in 44 cities, $2.74, and for bitulithic pavements in 59 cities, $2.06. These figures are all for work laid in 1912. '^o figures are given for sheet asphalt, but a compilation made in 1911 for 20 cities shows an average price of $2.03. ]\rost of the figures given include a guarantee of from 1 to 6 years. These figures are als(^ exclusive of grading in a large number of castas and are also subject to an addi- Coucrcic ]\()(f(ls and Pfii'ciiirnls. D rioiial ehavii'o for overhead expense, as in the case of concrete. The sitnation reo-ardinc,- the use of concrete for country roads is entirely different. The first cost is naturally much higher than some of the forms of con- struction which have heen considered good enough in the past. Concrete cannot hope to compete with ordi- nary dirt or gravel roads in first cost ; but when its advantages of long life and low maintenance expense become fully established it Avill replace these, at least on most of the main highways of this country, and even on less important roads where the population and wealth are sufficient to make it possible. The eighth annual rejwrt of the Commissioner of Highways for the State of Maine, for the year 1912, contains a summary of the work done, in which is in- cluded six contracts on concrete roads totaling 21,128 square yards and averaging $1.52 a square yard. This roadway all has bituminous top coating. This figure includes all expenses, such. as grading, manholes, drains, engineering and superintendence. Even at this, it is scarcely a representative figure, as it includes 1,000 square yards at South Portland, which ran up to a price of $2.10 per square yard, owing to the fact that a large amount of rock base had to be put in. Leaving out this contract the five remaining contracts show a total of 20,128 square yards put in complete at an average fig- ure of $1.1:0 per square yard. DuraJjility. While concrete has not been used as a road-making material long enough to determine its life in this use from actual experience, very fair in- ferences may be drawn from the general behavior of concrete under wear, as well as from the behavior of 10 Concrete Roads and Pavements. such pavements as have been in use for a considerable length of time. In taking, account of this latter item, however, due allowance must be made for the fact that the first concrete roads, like the first concrete build- ings, were not constructed in accordance with present- day practice, and were far from reaching the degree of perfection which is now attained. There are two elements to be considered in deter-- mining the suitability of a material for a roadway — its wear under the elements and its resistance to traf- fic. That concrete can qualify under the first of these requires no argument. It has proven itself able to withstand any attack of atmospheric conditions, condi- tions of soil, fire, etc., at least as well as the best of natural stone, as is amply shown by the large num- ber of miscellaneous structures, under all kinds of conditions, which it has to its credit. While one may point for confirmation of his as- sertion of the durability of concrete roads to a large number of such roads which are standing up most successfully under traffic, perhaps one of the most con- clusive proofs of the value of concrete for this purpose is to be found in the comparative tests which have been made at Detroit with a device known as a paving determinator. This device was designed and built by Mr. John C. McCabe, boiler inspector of Detroit, for the Department of Public Works, with the idea of sub- jecting sample pavements to wear as closely approxi- mating actual conditions as possible. Eight sections of as many different kinds of pavement were first tested by this machine, a concrete section built under the Wayne County specifications giving by far the best Concrete Roach and Pacenients. 11 wear. Full details of the tests made by this machine are given in Chapter XI. Comparing concrete and macadam pavements, Mr. Logan Waller Page, director of the Office of Public Roads, made the following statement before a meeting of the Association of American Portland Cement Manu- facturers in 1912 : '^In the matter of sustaining normal loads the ca- pacity of concrete pavements as compared with the capacity of ordinary macadam or bituminous macadam surfaces must be superior. J^umerical data or experi- mental evidence on this subject is as yet meager. It is not difficult, however, to draw^ certain definite conclu- sions when we consider the nature of the materials in- volved. It is well kno^^^l that macadam roads have rutted under heavy loads. For ruts to develop rapidly it is quite evident that some shearing of the macadam surface occurs. Of course, rutting also takes place^ because of wear and lateral displacement of stone. The capacity of concrete pavements to resist shear is rela- tively much greater, and we may perhaps note this as the first point of superiority of concrete over macadam pavements for sustaining normal loads. ^^It is common practice to assume, in designing concrete bridge floors, that normal pressures over an area are transmitted through the slab in lines of pres- sure whose boundary surface is conical, with elements at an angle of 45 degrees or more with the horizontal. It scarcely needs demonstration that the same assump- tion cannot hold for macadam slabs, i. e., normal pressure cannot be transmitted by a macadam slab over as large an area of the sub-grade, and this, it is rea- 12 Concrete Roads and Pavements. sonable to record, is a second advantage of concrete over macadam construction. ^^A¥e may, if we choose, compare concrete road surfaces with macadam road surfaces, assuming that each is an arch between curbs. It is not difficult to sec that concrete is superior as an arch in the following Avav: Consider the entire sub-grade carefully re- moved from a macadam road surface; there is some doubt as to whether the macadam surface would stand alone. On the other hand it is easy to see the com- plete concrete slab crown not only standing after the removal of the sub-grade, but to also see this arch of concrete sustain considerable load without a sub-grade, so that we must admit the third superiority of concrete roads over any macadam construction in their action as an arch to sustain normal pressure. ^Trom the comparisons made above between Port- land cement concrete and plain macadam or bituminous macadam, it is evident that we may be practically assured that the Portland cement concrete road is far better able to meet the changing traffic conditions than either of the other materials. From our knowledge of the strength of Portland cement concrete, we can de- sign a road surface of this material to meet practically any traffic requirement." Ease of Cteaning. The fact that Mr. Tillson as- signs to this item a value of 15 is conclusive proof that he has city pavements primarily in mind. Even under this high valuation, however, concrete pavements can qualify for a ]dacc equal to any. The fact that concrete is laid in large units is of itself perhaps a suf- ficient recommenchitiou on this point. This gives broad ex])anses of reasonably smootli surface to be cleaned. Concrete lloads (iiid Pdrenieiils. Vd free from freciTiciit joints, and the irregularities in sur- face which always n^snlt from tlie use of small units — surfaces easily cleaned Avith brooms or mechanical cleaners, or flushed with a hose. The only pavement to which it can be compared in this respect is sheet asphalt ; but this latter acquires so much unevenness of surface in the course of a few years, due to the un- equal bearing strength of the various parts of the sub- grade, that water does not readily flush it clean, and thorough cleaning with mechanical cleaners is almost out of the question. The concrete pavement, on the other hand, both by reason of the fact that it retains its true shape indefinitely, and because of the nature of its surface, is admirably adapted to the economy of mechanical cleaning. Col. George E. Waring, Jr., when street cleaning commissioner of Xew York City, made the statement that he could save the city $500,000 a year in the cost of cleaning if all the streets Avere paved Avith asphalt. Concrete paA^ement Avas not knoAvn at that time ; but Avith its advantage OA^er asphalt, as above pointed out, concrete could be expected to effect an cA^en greater saving. Resistance to Traffic. By this is meant the amount of friction dcA^eloped betAveen the pavement and mov- ing A'-ehicles, this factor gOA^erning the load AA'hich any giA^en power can haul over a road. As the amount of this friction varies Avith different materials, it stands to reason that the most economical roadway, other things being equal, is the one in Avhich this friction is least. Prof. Arthur H. Blanchard, of the Highway En- gineering Department of Columbia University, con- 14 Concrete Roads and Pavements. siders sheet asphalt as the perfect pavement in point of ease of traction, assigning it a value of 10 on this point in making up the characteristics of an ideal pave- ment. To concrete he gives a value of 9, and to earth roads 2, other materials taking various intermediate values. He has given concrete a high place, to be sure, giving a better rating to only one other material; but we believe even this scarcely warranted. The elasticity and resiliency of asphalt do not make for ease of trac- tion, but rather the reverse; for an asphalt pavement, with its slightly yielding surface, is a nearer approach to a dirt road than an unyielding surface of concrete. Granting Prof. Blanchard to be correct, however, his- rating could only apply to a perfect asphalt surface, true to line in every direction, which is something sel- dom to be found, and which the pavement rapidly de- parts from, even if conforming to it when first laid. On the other hand, as already pointed out, concrete holds its original shape, subject only to slight and usually uniform wear. Taking it in another way, it may be stated that to move a weight of one ton will require a tractive force of 100 pounds on a dirt road, 40 pounds on macadam, 25 pounds on brick pavement and 20 pounds on con- crete; in other words, that a horse on a concrete road- way can draw five times as much as on a dirt road and twice as much as on macadam. Non-Slipperiness. This is a factor which is more tmder the control of the builder in concrete than in any other material, it being possible to make the sur- face of almost any desired texture. Ease of Maintenance. While we continue to fol- low Mr. Tillson's headings, this might perhaps better Concrete Roads and Pavements. 15 have been ''Cost of Maintenance/' although each term may by inference be made to include the other. It is the cost of maintenance, however, which goes into the records of a municipality, and by which the success or failure of a pavement will very largely be judged as the years go by. On this point alone concrete is des- tined to win a vast number of friends as its low main- tenance cost becomes generally known. Consider for a moment this question : What is the maintenance cost of a well-laid basement floor or a properly constructed concrete sidewalk ? True, some floors will require an occasional patch and some walks an occasional square replaced; but equalize these charges over the total life of the structure and it will be found that the annual charge is very small indeed. So it is with a concrete roadway — the first cost is prac- tically the only cost, requiring ridiculously small ap- propriations for maintenance, and allowing municipal- ities and road districts to spend most of their money on new" construction. The oldest concrete pavement of which the writer has knowledge was built at Belief ontaine, Ohio, in 1893 and 1894. This pavement contains 4,400 square yards and was built in two courses. On December 14, 1912, Mr. C. A. Inskeep, city engineer, stated that the ap- proximate total cost for repairs had been $200. When laid the pavement was cut into squares, sim- ilar to those commonly seen in cement concrete side- walks, and the principal part of the wear has been along the longitudinal joints thus formed. The wheels of vehicles form grooves at these places which they have a tendency to follow. Eepairs have usually been made with cement mor- IG Concrete Roads and Pavements. tar or concrete, which has been placed in the grooves after they have been chiseled ont. Sometimes this patch has been dovetailed in; that is, the sides of the notch incline towards the axis of the groove rather than out- wards. In some places paving bricks, laid crosswise, have been cemented into the prepared notch instead of mak- ing the entire patch of concrete. This has. been done when it was impracticable to keep traffic off the street long enough for a concrete patch to harden. If the reported figures are accurate, the total re- pair cost has been only 4. 77 cents per square yard in .18 years, or 0.265 cent per square yard per year. In their report for the year ending September 30, 1912, the highway commissioners of Wayne County, Mich., state: ^^The only surface repair required on our concrete roads has been the refilling of the con- traction joints with tar and sand on the roads first con- structed, where the joints were not protected with armor plates. The cost of refilling these joints did not add to exceed $100 all told to our maintenance costs." The maintenance cost of an asphalt pavement runs from 5 to 35 cents per yard each year, depending on the quality of the first installation and the state of repair demanded by the city. In some thickly popu- lated districts the maintenance of a macadam pavement has been known to cost as much as the original con- struction, meaning a practical rebuilding each year. Figures collected by the Office of Public Koads relative to the cost of maintenance of plain macadam and bituminous macadam pavements under fairly heavy traffic conditions indicate that these pavements, when Concrete Boads and Pavements. IT properly maintained, entail an annual absolute main- tenance charge of approximately $450 per mile per annum for plain macadam, and possibly from $800 to $1,000 per mile per annum for bituminous macadam, for 15-foot surfaces. These figures have led Mr. Logan ^Valler Page, director of the Office of Public Roads, to believe that we must seek a more permanent form of pavements for country road surfaces. Favorahleness to Travel. By this is meant the ease and comfort of riding, as well as the reduction of wear and tear on vehicles to a minimum. The fact that concrete is placed in large and unyielding sections is perhaps a sufficient argument for it in this regard. There is not the frequent recurrence of joints found in many other tyjDcs of pavement, tending to wear the vehicle and reduce the comfort of passengers, even when such a pavement is at its best; while the dete- rioration of many small units, the rounding of the edges and the gradual settling in spots as traffic pro- gresses, produce an increasing unevenness and corre- sponding discomfort. A concrete pavement not only presents a broad expanse of unbroken surface, as has been spoken of before, but it has within itself sufficient strength to bridge over weak spots in the sub-grade. In October, 1911, Mayor Gaynor of 'New York appointed a special committee on pavements, to investi- gate and report to him on the condition of the pave- ments of that city. In making its report this commit- tee said : ''JSTo quality which a pavement can possess is more important than smoothness. Every irregularity in the surface is a source of weakness and of ultimate failure. As the wheels are drawn over the road, the wear which 18 Concrete Roads and Pavements. they cause is almost in proportion to the obstacles en- countered. If the pavement is rough, as our stone ones are, or if it be broken, the wheels pound, and the pave- ment is subjected to heavy blows Avhich soon wear it away and otherwise destroy it. In almost all our stone pavements one can find places where the blocks have actually been crushed or split from this cause.^ If the pavement is of wood block, asphalt or any other com- position material, and the surface is wavy, the depres- sions will hold water and speedily lead to failure; in such pavements disintegration almost invariably com- mences in these places. In luacadam roads, depres- sions of this sort are the chief cause of wear, and especially so since the introduction of the automobile. The rapidly passing wheels throw out the standing water with great violence, carrying with it the binder or fine stuft' between the stones, thus causing the pot holes Avhich make their appearance so rapidly on sucli roads when subjected to heavy automobile traffic. ''It should be remembered that since the advent of the automobile, smoothness for pavements is an even more important quality than it was formerly. The shock which a swiftly moving vehicle receives when it meets an obstruction, is more violent and destructive in its effects than if it were proceeding at a more moderate gait, and no matter how the force of the blow may be disguised from those riding in the car, by springs, pneu- matic tubes or otherwise, the destructive effect of the blow remains the same and is absorbed by some part of the mechanism, causing injury either to the tires or frame. ''The loss sustained yearly by the citizens who Concrete Roads and Pavements. 19 use automobiles, by reason of the roughness of our pavements, must be very great in the aggregate.'' Sanitariness. On this last point it will readily be conceded that concrete has no equal as a road and pavement material. It contains in itself nothing vrhich can decompose or become objectionable ; it offers neither a porous surface nor numerous joints for the collection of street refuse, where it can decay and become a menace to public health. Any liquid refuse which might pene- trate the surface of a concrete pavement, which will be smaller in amount than on any other class of pave- ment with the possible exception of sheet asphalt, will, to a large extent, be neutralized and made harmless by the lime in the concrete. CHAPTEE II. The Construction of Concrete Roadways. While practice in the construction of . roads and pavements will differ in different localities, because of A^arying materials, equipment, and other conditions, thi.^ writer feels that he can do no better than to recommend a close study of the specifications of the ^N'ational As- sociation of Cement Users in Appendix A, or the A7ayne County Specifications, in Appendix B. There are, as is perhaps generally well known, two general types of concrete pavement, designated by the terms One Course and Tiuo Course. The former of these is laid of one mix of concrete throughout, and ])laced in one ojDcration; while the latter has a base of a lean mix with a wearing surface richer in cement, and usually with a harder and more wear-resisting aggre- gate. While- it may be said that the one-course roadway seems to be growing in favor, the determination of the type to be employed must be governed largely by local conditions. If, for instance, the aggregate most readily available is of a soft nature and readily crumbles under abrasion, a better and more economical pavement will be secured by using this in a base course, with a wear- ing surface in which granite or some other hard rock is used as an aggregate. This small amount of granite will take the wear of traffic, while the bottom course with the local aggregate will have sufficient strength foi' a foundation. Some cities which are putting in (20) Concrete Boads and Pavements. 21 large aiiioimts of coiicrett' paving, such as Mason City, Iowa, find it advantageons to follow this method. In other localities, where there are available deposits of hard gravel, or other stone suitable for this work, which does not have a sufficient market value to make its use extravagant, a one-course roadway can be laid to good advantage. While this type requires slightly mow cement per yard, the labor cost is less ; in localities where cement is high in price, however, these two items will have to be balanced against each other, though it ^vill probably be found that any difference will be in favor of the one-course type in almost every case. This type, also, leaves no possibility for the separation of the wearing surface from the base, as may happen in a two-course pavement if sufficient care is not exercised in laying. Suh-Grade. The sub-grade may be either flat or curved to the crown of the finished road. While there may be certain advantages of construction in this latter method, and while it is perhaps more frequently fol- lowed than the other, it is the belief of some of the best road builders that a better roadway can be built on a flat sub-grade. Their position is, it would seem, well taken. It is at once apparent that this will give greater thickness, and consequently greater strength, in the njiddle of the pavement, where greater strength is needed. A plotting of all the strains on the pavement will show this design to have additional advantages. A flat sub-grade also facilitates the ^^crawling" of the pavement due to expansion and contraction, and thus lessons the tendency to crack. For this latter reason, too, the sub-grade should be smooth, free from humps or depressions. Soft and 22 Concrete Roads and Pavements. spongy places must be removed and filled in with the same material as the body of the road. The sub-base must be kept wet while being compacted, and also should be thoroughly wet when the concrete is deposited, in order that the water in the concrete may not run away. If the subsoil is of a character to retain water, it is very important that such a system of underdrainage be installed as will carry the underground water from beneath the road. In the dry summer weather this work may not appear necessary, but information should always be obtained regarding the action of the subsoil during the wet season and when frost is coming out of the ground. There are, of course, many soils of a gravelly, sandy, or other character which are self-draining and do not require particular attention, but it is a fact that the defects in most of our country highways which are built upon clay soils or those which do not drain themselves, are to be attributed to a lack of drainage. There are two general methods in use to dispose of the water. One is to lay a 3- or 4-inch land tile under the shoulder and about 12 inches outside the edge of the concrete. The ends of the tile should be placed close together and clean stone of at least 1%-inch size put on the sides and top of the tile to a depth of 3 or more inches. If there is any danger of dirt reaching and getting through the joints, the upper half of the tile at the joints should be covered with paper before the stone is put upon it. The other method is to lay a French drain in the same position. With this type of drain the best results are obtained by placing in the bottom flat stones of 6, 8 and 10-inch dimensions. Those should be laid in the form of a culvert and should be covered to a depth of Concrete Boads and Pareiiwnts. 25 about 6 inches with smaller stone of not less than IV2- inch size. The width of the ditch should be about 12 inches. In both cases the depth of the bottom depends upon the character of the subsoil, but should in no case be less than 18 inches below the finished grade of the road at the crown. Materials. In order to j)i*o<^^T^^ce the most satis- factory roadway, the aggregate for the wearing surface should be ^^sufficiently hard to scratch glass." Natural mixed aggregates as they come from the deposits should not be used. It has been found to conserve both economy and durability to properly grade the ma- terials. Suggestions for the proportions of materials of the various sizes will be found in some of the speci- fications ; but this, too, has to be governed somewhat by local conditions, and on work of any extent it will be worth while for the engineer to make a careful study of the materials and work out a formula for use on that particular job. The materials must be clean, free from loam or organic matter, as these will, if they should come at or near the surface, inevitably result in holes. Proportions. The Wayne County mix for one- course roadway of l:lV2:o is perhaps the last word on this subject, as it has been arrived at after a great deal of study and experiment. It is practically the same as the specifications of the ^N'ational Association of Cement Users, which recommends ^^not more than 2 parts of fine aggregate." The Wayne County mix is not only giving remarkable results in actual practice, but has passed surprising tests, as detailed in another chapter. ^Xot all roads, however, will be called upon to endure the same heavv traffic as those of Wavne countv, and in 24 Concrete Roads and Pavements. many localities a 1 :2 :4: mix will very likely build a road which will meet all requirements. For a two-course pavement the best practice re- quires a base of 1:2% :5j or 1:2:5, with a 1 :2 wearing- surface. Consistency. For a one-course pavement the con- crete may preferably be mixed so wet that it will flow into place with only slight spading. The base of a two-course pavement cannot be quite as wet as this, but will usually require light tamping before the top surface is put on. Methods of C onstruction. Aside from a good con- crete mixer, preferably of a type which can be moved readily along the work and deliver directly onto the sub-grade, very little equipment is required. Two-inch plank, the width equal to the thickness of the roadway, are placed on the sides of the prepared sub-grade and securely staked in position, the stakes being driven a little below the edge of the plank so as not to interfere with the movement of the template by which the surface is finished. Care must be taken that the planks fit close to the ground, so that the water in the concrete cannot run away under them. The mixer and the side forms are the basis of equipment. Various other things may be used at differ- ent times, such as carts for hauling the materials to the point of deposit, but it must be borne in mind that the more nearly the materials can be distributed along the roadway in the quantities needed, and the more often the concrete can be delivered direct, the more rapid will be the ])rogress and the lower the unit cost. A good ])1an of organization for carrying on con- crete road Avork, and based on practice in Illinois, is Concrete Roads and Pavements. 25 to divide the work in two parts, each under a competent foreman or superintendent. The first party will do the grading, prepare the sub-grade carefully and haul the aggregate on the roadbed in such quantities that there Avill be sufficient to provide for the concrete. It is bet- ter, however, to have slightly less than too much aggre- gate in the roadway, as it is more economical to haul in an extra load or two to make up any deficiency tha! may occur than to dispose of a surplus. It should be borne in mind for estimates for this part of the work that there will inevitably be a small amount of aggregate left on the roadbed, which is by no means a bad feature, so that there should be allowed a full cubic vard of gravel or stone for each cubic vard of concrete to be laid. The second j^arty comes upon the work with the concrete mixer and starts in at one end of the road to mix and j)l^ce the concrete. With an automatic dis- tributing type of machine, five to seven men will be about all that can be used advantageously in shoveling the material into the hopper. Two men will be required on the machine, one man to clean up as the machine ad- vances, so that the concrete may be placed on a clean roadbed ; two or three men taking up the forms as used and putting them ahead ; three men to strike the work, using the template, and two finishing with floats. Par- ties so made up, with a 12 -foot capacity mixer, will lay from 500 to 800 square yards of T-inch concrete a day of ten hours. The teams necessary for this part of the work would be only those required to haul the cement and an occasional load of gravel as deficiency may be experienced. There are sections of the country Avhere continued 20 Concrete Roads and Pavements. siiltrj Slimmer weather prevails when it will be neces- sary to work the shovelers in two gangs, working from 15 to 20 minutes each. Either this must be done or the progress of the whole party reduced to about one-half what it is in cooler weather. A third party might be organized to trim* the shoulders and attend to final finishing of the sides and ditches. Surface Finish. The surface of a road should not be finished smooth, but left slightly rough. This may be done by the workmen using a wood float, or it may be done after the work has been floated fairly smooth by slightly marking the surface with a broom. This latter method is perhaps better adapted to rock and sand concrete than gravel concrete, as the latter will leave many small pebbles in the surface and not finish Avith so smooth a mortar surface as sand and rock con- crete. Brooming should be done from side to side of the roadway rather than lengthwise. On city pavements a smooth finish is sometimes desired, though even here a rough finish would seem to be preferable. Where a street or road is on a grade of more than 4 per cent, the concrete should be marked off with transverse grooves to prevent slipping. When a concrete roadway is to be supplemented with gravel shoulders, the edge of the concrete is usually trimmed off slightly when the side rails are removed, so as to prevent an abrupt line between the concrete and gravel. Expansion Joints. These are treated separately in another chapter. Protection. Even if a good mixture has been used, Concrete Boacls and Pacenients. 27 a bad pavement may result if proper care is not taken to supply an abundance of moisture while the cement hardens. Shrinkage cracks occur if the concrete has not been covered and kept thoroughly moist, for a period of not less than two weeks. A good method to secure proper curing is first to cover the concrete with canvas as soon as it has taken an initial set so that it will not be marred. The canvas is kept moist, and then in a few hours, or as soon as the road becomes set, sand or earth is shoveled upon it and kept wet. Mr. A. X. Johnson, engineer of the Illinois State Highway Commission, calls attention to the fact that each batch of concrete as deposited in the road should be watched, that the mortar does not flow to the edge of the pile and leave a core of aggregate unsupplied with sufficient mortar. At least one workman should be as- signed to shovel all such cores of aggregate to the bottom of the concrete layer so as to insure only cement rich in mortar at the surface. If this is not done, depres- sions will develop in the surface under traffic which will loosen the clusters of pebbles of the aggregate which do not have sufficient mortar to hold them fairly in place. The men finishing the surface should be warned not to let such places go by them without shoveling out the pebble clusters and replacing them with a richer mix- ture. A finisher can easily cover such a place by work- ing a film of mortar on the surface without necessarily filling the voids below. Use of the Template. The template should be ]nade of wood, very rigid, and cut to the crown of the road, and should have two handles on each end so as to make easier its operation. A man at each end works it back and forth and at the same time moves it slightly 28 Concrete Roads and Pavements. forward. This side motion requires that the template be about tAvo feet longer than the width of the road. When there is an excess of material, it is necessary to use the template as a scraper — getting the approximate shape — and go over this section again with the back- and-forth motion. By the use of a sloppy wet mixture the template worked in this manner gives the concrete sufficient tamping and brings to the top sufficient mortar, to produce an even surface. If, however, the stone used in the concrete is too large — over 1^/4 inches — the tem- plate will drag the large pieces along and leave holes behind the template. In moving the template forward, it is pointed out by Mr. W. A. Mclntyre of the Association of Portland Cement Manufacturers, that some of the larger stones are pidled from the surface and collect in front of the template, making the operation hard to perform, expos- ing a lot of uncoated stone, and causing water carrying cement to run off the sides. The stones should be scraped forward by a man with a shovel, and deposited in the bottom of the concrete layer. In running the template over the surface a second time, rich mortar collects as did the stone the first time, and has a ten- dency to run off at the sides. This should be scraped forward the same as the stone. Care should be taken in moving the template for- ward that it is not lifted from the side forms and moved two or three inches at a time. Such an operation will leave the surface full of little undulations and make the road noisy and uncomfortable for travel. After the template lias been used the surface of the concrete is left quite wet and in a condition which will not give good results if troweled at once. Concrete Roads and Pavements. 29 Sufficient time should elapse in order that the ex- cess moisture will be absorbed or evaporated and then the surface should be troweled with a wooden float wherever necessary. The time between using the tem- l^late and floating depends upon the condition of the weather, but is usually about thirty or forty minutes. Care should be taken not to overtrowel and thus bring- to the surface too much fine stuff. Troweling should be done from a bridge spanning the road and resting upon the side forms. Then there is no danger of the wet concrete being disturbed by placing planks upon it or by the finishers trying to take in too large an area without moving and stepping upon the surface. Such a bridge is cheap and has the added advantage of allowing the workmen a short cut from one side of the road to the other. Comparison of Hand and Machine ^Yorh. Mr. C. II. Hubbell, of Davenport, Iowa, made some interest- ing comparisons on work done in 1911 and 1912, hand mixing being used in one year and machine mixing the other. ]\Ir. Hubbell reported his findings in an article in Municipal Engineering, summarizing the work as follows : Hand Machine Mixing Mixing cii. yds. cu. yds. Average yardage per man on street pavement (except watchman, water and sack boys) 2.31 3.83 Average yardage per man on street pavement (including all engaged in the mixing operation) 3.04 4.788 Cost per cu. yd. of street pavement (includ- ing only wheelers, loaders, mixers and spreaders) $0.64 $0,508 Cost per cu. yd. of street pavement (includ- ing all engaged in the mixing operation). 1.075 0.74 The machine used was a Xo. l-t Koehring special ;]0 Concrete Roads and Pavements. paving mixer, whicli gave an average yardage of 200 per day with the following gang : In Front of Machine: 3 stone wheelers, 8 stone loaders (two loaders per barrow), 3 sand wheelers and loaders (two barrows), 1 cement wheeler (three sacks per load), 3 machine men (fireman, engineer, bucket man). At Rear of Machine: 2 spreaders, 1 tamper, 1 template setter and block placer, 2 finishers. The following calculations show the detailed labor costs of job Aj as Avell as summaries of the unit costs of jobs A, B, C, and J), of the work above referred to: Job A, 3,100 Sq. Yds. Base 5 in. 1:3:5. Average output equals 530 sq. yds. Time 5.7 hrs. Total 9 men on rock at 22i^c $11. 5o 3 men on sand at 22 ^/^c 3.85 1 man at skip at 22V^c 1.28 1 man wheeling cement at 22 ^c 1.28 1 man leveling concrete at 25c 1.43 1 helper leveling concrete at 22V^c 1.28 1 tamper at 22i^c 1.28 1 engineer at 25c 1.43 1 fireman at 25c 1.43 1 bucket operator at 15c 0.86 1 water boy at 05c .28 1 foreman at 45c 2.57 Total $28.80 Wearing surface, 1^2. in. 1:1:1. Average output, 530 sq. yds. Time, 2.8 hrs. Total 4 men on granite chips at22i/^c $ 2.52 4 men on sand at 22i/^c 2.52 2 men on skip at 22i^c 1.26 Per sq. yd, $0.0218 0.0073 0.0024 0.0024 0.0027 0.0024 0.0024 0.0027 0.0027 0.0016 0.0005 0.0048 $0.0543 Per sq. yd. $0.0048 0.0048 0.0024 Concrete Roads and Pavements. 31 2 men wheeling cement at 22V2C 1.26 0.0024 2 rough spreaders at 221/20 1.26 0.0024 1 fine spreader (also tamps top) at 25c 0.70 0.0013 1 fireman at 25c 0.70 0.0013 1 engineer at 25c 0.70 0.0013 1 bucket operator at 15c 0.42 0.0008 1 water boy at 05c 0.14 0.0002 1 sack boy at 05c 0.14 0.0002 1 foreman at 45c 1.26 0.0024 Total $12.88 $0.0245 Finishing (530 sq. yds.) 1 finisher, 13 hrs at 25c $3.25 $0.0061 1 helper, 13 hrs at 22y2C 2.93 0.0055 Total $6.18 $0.0116 Form Setter. 1 man, 10 hrs. . at22y2C $2.25 $0.0042 Miscellaneous. 1 man trimming grade, 10 hrs $2.25 $0.0043 2 men cleaning up stone, sand, etc., while top is being placed, 4.3 hrs. each 1.49 0.0036 Total $4.19 $0.0079 The time required for moving the machine was 15 hours for 8 moves. The wearing surface organiza- tion is charged with moving the machine ; so to arrive at cost take 1.5/2.8x$12.S8, which equals $6.00. Unit cost equals 0.013 per square yard. Summary, Job. A. Per Per sq. yd. cu. yd. Development expenses $0.0090 $0.0500 Watchman 0.0050 0.0277 Base 0.0543 0.3008 Top 0.0245 0.1357 Finishing 0.0116 0.0643 Setting Forms 0.0042 0.0233 Miscellaneous 0.0079 0.0438 Cleaning street, boulevard, etc 0.0055 0.0305 Moving machine 0.0130 0.0730 Total $0.1350 $0.7481 o"2 Concrete Roads and Pavements. Summary, Job B (2,300 Sq. Yds.) Per sq. yd. Development expenses , $0.0088 Watchman 0.0048 Base 0.0526 Top 0.0237 Finishing 0.0112 Form setting 0.0041 Miscellaneous 0.0071 Cleaning street, boulevard, etc 0.0054 Moving machine 0.0125 Total $0.1302 . Laborers' wages were 22 1^ cents per hour, and condi- tions were almost identical with those of Job A. Summary, Job C (3,500 Sq. Yds.) Per sq. yd. Development expenses $0.0185 Watchman 0.0060 Base 0.0595 Top 0.0268 Finishing 0.0122 Form setting 0.0047 Miscellaneous 0.0080 Cleaning street, etc 0.0061 Moving machine 0.0141 Total $0.1514 Laborers were paid 25 cents per hour on this job. De- lays were frequent, due to shortage of rock, sand and men. Summary, Job D (1,600 Sq. Yds.) Per sq. yd. Development expenses $0.0155 Watchman 0.0060 Base 0.0584 Top 0.0260 Finishing 0.0120 Form setting 0.0042 Miscellaneous 0.0080 Cleaning street 0.0041 Moving machine 0.0130 Total , $0.1472 I quoting extensively from these addresses. (33) or contraction, as I believe aterprooflng the surface in our climate ovides for same. The alley in question Tries a heavy teaming traffic and so far ows no evidence of deterioration. The St under private contract was 13 cents r square foot, with gravel at $1.10, sand e same, and cement $2.50 a barrel. Labor .00, teams $4 to 5, oil 90c barrel (42 gal.), nuch prefer crushed rock and screenings same properly proportioned, not exceed- ; 1 inch in largest size of aggregate, and mt machine mixed concrete with power raying in two or three light coats of not ceeding % gallon to yard, all told. In is particular instance the rock was too arse (Max. 3 inches) for a floor of 4 ches, though power mixed, and the oil was iplied in one coat by gravity, and in too eat quantity, showing a tendency to run center. Generally speaking, I am in vor of flat crowns for asphalt or concrete ads, conditioned upon ample longitudinal 11, as conducing to more uniform use of itire width of street. We had nearly 3 iles of various forms of asphalt last year, informing generally to a 6-inch crown for width of 46-foot roadway, and experience IS demonstrated that the traffic does not inter, but is uniform over the entire width : roadway, thereby conducing to the life ' pavement. Pomona lies upon a plane of om 1 to 2% per cent grade, and most of however slight, for the effect if nothing else. For a width of 46 feet six stakes are ample for section and 10 feet to 16 feet longi- tudinally, as required by the character of the work and in forming an intersection of streets as many as 60 or 70 stakes are re- quired." Highland Park, 111.— Jas. Shields, city en- gineer, like many of the other engineers, takes occasion to state that their pavement is in flrst-class shape. He states also that the price of $1.01 includes materials, labor, etc., but not engineering inspection and superintendence. A tile drain was placed 3% feet below the street grade under each curb and back filled with cinders to keep water from under paving. He says that the citizens are very much pleased with the paving. Richmond, Ind. — Fred R. Charles, city en- gineer, supplements his report with this statement: "In paving between car tracks the ties are bedded in concrete the usual way, and the foundation connects up to the top of ties; when fully set, the surface is sprinkled with sand to form a joint of sepa- ration, and concrete made 1-3 proportions, is filled in to top of rails, and stuck off with a template cut the proper shape to give the groove for the wheels along the rails. Sur- face of concrete is finished by floating rough. Marshalltown, Iowa. — W. H. Stein, city a considerable amount of concrete pave- ment in previous years, beginning with 1907, and Mr. Brian Bradbury, .Jr., commissioner public works, says that it is wearing well and there has been no cause as yet for main- tenance Alpena, Mich. — This city built some con- crete pavements in 1909 and 1910, and Jos. W. MacNeil, city engineer, says that it is all in good shape. Ann Arbor, Mich. — This city has done a considerable amount of paving, beginning with 1909, and Manley Osgood says that it is wearing, very well where laid in two courses. He adds that the citizens like it very much. Minneapolis, Minn. — This city has tried concrete paving for the first time, and likes it so well that it will do further work of the same kind. The price given in the table is based on gravel at $2 per yard on the job, cement at 86% cents on the car, sand at 75 cents on the job, and labor at $2.40 per eight-hour day. Kansas City, Mo. — Mr. Clark R. Mandigo, assistant city engineer, states: "There were 52 public contracts let tor paving streets with concrete, aggregating 12.1 miles, or 198,443 square yards. This pavement called for a total cost of $211,148. This includes sub-grading, a five-year guarantee, and pay- ment in tax bills against the abutting prop- yards. This was laid at an average cost of $1.10 per square yard, under the same speci- fications and conditions that the street pav- ing was laid. In addition to the public con- tract work, 2.8 miles of concrete pavement, or 38,500 square yards, was laid by private contract, under the supervision of the en- gineering department. It will, therefore, be seen that Kansas City put down over 250,000 square yards of concrete pavement during 1912 — probably more than any other city in the United States." Trenton, N. J. — Harry F. Harris, assistant engineer of streets, reports work done in 1911 wearing very good. The prices given include excavation, material and labor. He stated that after experimenting with both types of construction, his city is inclined to favor one-course method, using wet mixture of about 1-2-4 or l-iy2-3. Sheboygan, Wis.— C. U. Boley, city en- gineer, states that work done in 1911 does not show wear except a slight smoothness of the surface. The price given for rein- forced concrete pavement includes every- thing except engineering inspection. Aberdeen, Wash. — Chas. W. Ewert, city engineer, says that the work done in 1910 and 1911 is wearing in first-class shape, showing only a few hair-line contraction cracks. The work is given a brush finish. Price as given includes material and labor. For engineering he adds 2.9 per cent. DATA ON CONCRETE PAVEMENTS LAID IN MANY CITIES IN 1912. Connecticut- Sauth Noi Two Course Work -Base. Top. Day Labor Aggregate Used. Expansion Joints Soil or Cost Per Remarks Sq. Yds. So. Yds. Contract Yd. Mixer Previous To Be Done Thick, por- Tliic F Cotunib Highlan. Ft. Waj H-ndngto,, 49,800 Shreveport 10,600 .... '■•' uolarway surtace Maine— «SS HisLland Park... 12.500 24 5 1-3.5 2 1.2S4 Trap rock in wearing 3o"f'':Vter7oi„ts. Clay Kalamazoo 206 42 5 1-0 2 1-2 CrS'.T' stone and S6 ft. both directions Grave Ne^"v'i",r Norwal Sheboygan" 2r>.tJO0 .eX„"- Dolarway surface CHAPTER III. The Koads of Wayxe Couxty, Michigan. The concrete roads of Wavne County, Michigan — the county in which Detroit is located — haye become deservedly famous and are inspected almost daily by parties of road builders from other parts of the country. There are at least two good reasons why these roads are worthy of special consideration. In the first place, the people who haye built them approached the subject of roadmaking with open minds, intent only on getting a road which would best stand the traffic, and without a predisposition to fayor any one material above another; the final adoption of concrete means, there- fore, that this material proved itself to be, in their best judginent, ahead of any other.. In the second place, once having adopted concrete, they exercised the same openmindedness regarding their methods of construc- tion, revising their specifications and practice from year to year as their experience has shown this to be desir- able. Their present specifications, as given in Ap- pendix B, probably represent, therefore, the very best practice now in use anywhere. Mr. Edward X. Hines, a member of the board of road commissioners of Wayne County, has devoted a large amount of time to the development of the concrete road, and has told in a large number of public ad- dresses throughout the country what Wayne County is doing. A good idea of this work can be gained by quoting extensively from these addresses. (33) 34 Concrete Uoads and Pavements. ^The experience of the Wayne County Road Com- mission is particularly valuable because we were not committed to concrete at the outset/' said Mr. Hines before the Association of American Portland Cement Manufacturers in May, 1912. ^^Detroit is the heart of the automobile world, and the number of automobiles owned per capita is comparatively very high. This A W^ayne County Road Before Improvement. new vehicle quickly demonstrated here, as elsewhere, the purely temporary character of many so-called good roads. The automobile picked up the good roads in fine particles and scattered them over the countryside. The modern demands upon highways necessitated new methods and new materials, and we used concrete to meet these demands. Concrete Roads and Pavements. 35 ''The Commission, when first organized, followed the accepted practice and started in to build bitumi- nous macadam roads; but after a year's experience in noting the wear upon them, foreseeing a constantly in- creasing maintenance charge, and harking to the world- wide cry, 'What shall we do to save our macadam roads from the ravages of the automobile?' decided that a change was not only desirable, but necessary, and we set out to find a more permanent and durable material which would approximate in initial cost that of a first- class macadam. ''After thoroughly investigating the subject, study- ing the experience of near-by smaller towns in the mat- ter of concrete crosswalks, inspecting concrete bridge floors, and noting the general satisfaction concrete was giving in other forms of construction, the grades of Finishing with W^ood Floats. 36 Concrete Roads and Pavements. material used, the light form of construction as applied to cross-walks and bridge floors, we decided that a con- crete road would come more nearly realizing the ideal than other forms. The points considered as being in its favor were : Comparatively low first cost ; low main- tenance cost; freedom from dirt (there being no detri- tus from a concrete road in itself) ; its comparative noiselessness ; ease of traction for vehicles of all de- scriptions, and the small crown necessary to get rid of surface water. While we were reasonably sure of our ground, we also felt that in case we scored a partial failure we could use the concrete for foundation pur- poses. ^'Three stretches of road, aggregating two miles, on varying subsoils and with differing specifications, were decided upon. ^'These roads are starting on their fourth year of wear, and barring some longitudinal cracks are as good as the day they were built, and practically nothing has been spent on their surface for maintenance. On the basis of three years' thorough trial, I stand committed to the use of concrete for country roads. I also believe concrete to be an ideal form of paving for village and city residence streets and alleys. This is not a state- ment born of enthusiasm on the spur of the moment, but a cold-blooded dollars and cents view, based on results attained and arrived at after careful consideration of all the facts available and experiences imdergone. 'Tt is to be expected that on our first experimental work we did not achieve perfection. We did not use the same care as we are today exercising in the selection of a clean aggregate or a good mix. Neither Avere we so careful about striking off and finishing the surface. Concrete Roads and Pavements. 37 I believe I am safe in saving that the concrete road? we are buikling today are 25 per cent better than our first efforts. We have abandoned entirely the construc- tion of two-course roads built of crushed cobblestone, because of the difficulty of securing a suitable supply of properly graded material of this character. Crushed stone also contains a greater percentage of voids to be filled, and we have standardized on the single course road. "Any commimity that wants a good road, a road that is cheaper for even a short time under fairly heavy traffic than any other good road, a road that is inex- pensively maintained, a road that is sanitary and dust- less, a road that is not slippery, a road that affords good traction for any type of vehicle three hundred and sixty-five days in the year, a road that in the long run, say ten, fifteen, twenty years, and longer, is the cheap- est of all good roads, should investigate the merits of concrete. "The results we have obtained can be secured anv- Method of Mixing and Delivering. 38 Concrete Roads and Pavements. wliere if strict attention is paid to detail, care used in the selection of good clean stone and sand, and the proper proportion of a standard brand of Portland cement used, coupled with good mixing and care in fin- ishing the surface so it will not be full of depressions. It will not pay to stint the amount of cement used if good results are expected, and there must be adequate, intelligent, and honest supervision." The following winter Mr. Hines spoke before the Pittsburgh Convention of the I^ational Association of Cement Users, from which address we quote : ^'With four years' experience as a guide, we have demonstrated in Wayne County that a well-built con- crete road is a practical form of construction which merits and will receive a more extensive adoption. Every test to which our work has been subjected only emphasizes its strong characteristics. The points con- sidered are, initial cost, ultimate cost (which includes maintenance), sanitation and freedom from dust, good traction for all types of vehicles, smoothness and ease of construction. "The initial cost of a good concrete road is little, if any, greater than that of a first-class bituminous macadam road. One of the greatest fallacies indulged in by communities starting to improve their highways, is that cheapness in cost of original construction of roads means economy and that the highway official who can build the greatest area of roads at the least outlay per square yard, is working for the community's best interest. "On one of the main highways out of Detroit, Grand River Road, the first two miles is tar macadam. If someone had offered to build this road absolutely Concrete Roads and Pavements. 39 striking- Off the Surface. without one penny's cost to Wayne County, stipulating only that we should maintain it in a fairly average con- dition, at the end of eight years we would have been money ahead by rejecting the offer and building it of concrete under our present specifications. Of course, six years ago, when we built this road, we did not pos- sess this knowledge, but our experience was one of the reasons for abandoning the construction of this type of road and turning to concrete. When it comes to annual cost, the concrete road stands pre-eminent. With over sixty miles of concrete road in Wayne County, some of it in its fourth year, we have spent less than $300 on its surface for maintenance, and this is what makes this type of road the cheapest of all good roads. ^^WoodAvard Avenue Koad, now in its fourth year, shows little or no signs of wear and it is not built nearly so well as our latest constructed concrete roads. A conservative estimate of traffic on this road shows that over 1,300,000 vehicles (more traffic than would go 40 Concrete Roads and Pavements, over an ordinary country road in twenty years) have passed a given point, without the development of ruts, holes or bumps and with the expenditure of next to nothing for surface maintenance. On this same road, Woodward Avenue, adjoining our concrete at the 8-mile road, which is the Wayne and Oakland County line, Royal Oak Township this year built two miles of asphalt macadam at a cost of well over $1.00 per square yard. The first mile was opened for traffic August 17. On I^ovember 30 I went over this mile and counted 137 holes from one foot up to four, five and six square feet. Fifteen men, a steam roller and a couple of teams were at work patching and repairing and the road is not four months old. ''Whenever men interested in highway construc- tion get together they talk maintenance most emphatic- ally. While not belittling the principle of maintaining a road after it is built, it seems to me, with Wayne County's experience, it would pay other communities to adopt a form of construction on which it is not neces- sary to expend from $800 to $1,300 a mile yearly to keep it in fairly usable condition. Our concrete roads are sanitary, as there is no detritus from the road it- self ; there are few cracks and joints to hold dirt and animal droppings, and there is no dust. The drier the weather the less dirt on them, as vehicles do not track mud from unimproved cross-roads in dry Aveather. What little dirt is tracked on is immediately blown off or washed off by the first rain. ''Our concrete roads have a gritty surface and are not slippery in any kind of weather, affording good traction for all kinds of vehicles. Horses find good foot- ing on them and automobiles do not skid in wet weather. Concrete Roads and Pavements. 41 "It is not necessary to build concrete roads with any great amount of crown, and the tendency to drive in one track, so apparent on macadam roads by the formation of ruts, is eliminated, as the driver of a vehicle can sit comfortably in his seat, no matter on what part of the road he may be driving. Neither can a horse pick out the beaten track as on a gravel or macadam road. A crown of ^/4 inch to the foot dis- poses of the surface water and tends to distribute traffic over the entire surface of the road. "With all the other good points in its favor, con- crete can be handled with comparative ease, and provid- ing the work is carried on under skilled supervision, can be laid with a working force of relatively unskilled labor. It must be borne in mind, however, that the addition of a little cement to a quantity of stone and sand does not make concrete. There is no material which will respond so quickly to a little care, and if proper attention is given to the detail of mixing and curing, so well repay you in quality and permanence. With the foregoing in mind as to why we are con- tinuing to build concrete roads, I am going to take up a little more of your time and tell you how we are building them. "Drainage and good foundation are necessary for any type of road, and on a concrete road, the greater care that is taken in this respect, the better will be the final result. A well-drained, well-compacted sub-grade will eliminate cracks to a very large degree. ^'One of the bad features alleged against concrete roads is the tendency to crack. In order to overcome this tendency, we prepare our sub-grade as carefully as conditions permit, making it flat and rolling it hard 42 Concrete Roads and Pavements. A' i.k Striking Off. and firm. Due to temperature changes and the absorp- tion of water, concrete is constantly in motion and the flat sub-grade tends to overcome frictional resistance and thereby prevents longitudinal cracking. On the first concrete road we built, we crowned the sub-grade to conform to the finished crown of the road and used what I term, for want of a better name, an inverted curb. On this road and on the first concrete road built on Michigan Avenue, where practically the whole road is built on a fill, we have developed more cracks than on all subsequent construction. These cracks, however, are well taken care of at a small expense, by the use of a hot refined tar and sand. On our concrete roads it is the repair of these cracks that has made up surface maintenance cost, and with a well drained, well rolled, firm sub-grade, cracks of all kinds are reduced to a minimum and not to be seriously considered. "We build our roads in 25-foot sections to provide for contraction and expansion, believing it wise to make Concrete Roads and Pavements. 43 our lateral cracks beforehand so we can properly protect their edges from chipping and spalling. We are using a metal plate Avhich is a development of previous experi- ments. This plate is about 3/16 of an inch thick and 8 inches wide, provided with shear members which tie it securely to the concrete base and wearing surface. It is shaped to conform to the crown of the finished road and two thicknesses of three-ply asphalted felt (about %- inch) are inserted between the two plates of each joint. By the use of these plates we have practically overcome the wear at the joints, which is the weakest point in the concrete road, besides securing a smooth, even, con- tinuous finish." Wayne County is poor in good road material and everything has to be imported. The best results have been secured from the use of washed gravel, ranging in size from %-inch to 1%-inch, and washed sand from %-inch to nothing. An effort is made to have the ma- terial well graded so as to secure a dense concrete. Freedom from loam, clay or other foreign matter is absolutely insisted upon. These people believe in a rich mix, using one part of cement to three parts of stone, with just a little more than enough sand to fill the voids in the stone. They believe that the detail of mix- ing and curing the concrete have been as great factors in their success as any other feature. The roads are constructed with a minimum thick- ness of 7 inches. After the sub-grade is prepared, side rails of 2x7 inch lumber are placed, protected on top by a 2-inch angle iron. The concrete is laid right on the natural subsoil, which is well sprinkled just pre- vious to the placing of the concrete to prevent the water in the concrete being absorbed. 44 Concrete Roads and Pavements. A wet mix is used. 'No tamping is necessary, although a couple of men work in it with shovels. It is not considered wise or desirable to have the mortar and fine aggregate worked to the top as it i^ the stone vv^hich is wanted to receive the wear. After the con- crete is in place, no workman is permitted in any man- ner to disturb the finished surface by stepping in it or throwing anything on it. A plank trimmed to the curvature of the road and iron bound on the edges is used to give the road its proper shape. Two men saw this plank back and forth over the concrete, resting on the side rails or form board at the sides of the concrete, over which the strike-off rides smoothly. It is handled with sufficient care to eliminate the necessity for any considerable floating by the follow-up men. These fol- low-up men, or floaters, work on a bridge which rests on the form boards or rails at the side of the road so there is never any contact with the concrete. The flnal "smoothing up" is done with wooden floats of home manufacture. When the concrete has become suf- ficiently firm to permit the removal of the side rails, the finishers, to prevent a sharp division line between the concrete and gravel shoulders, pare off the outer edges which are formed next to the rails. Each day's work is finished up to an expansion joint, and no more than 20 minutes is permitted to elapse between batches during the day. The work of the day is covered with canvas, and the next day the canvas is removed, and to prevent the concrete from drying out too rapidly, it is covered to the depth of about 2 inches with any sand or loose soil that may be available. The concrete is sprinkled continuously for Concrete Bonds and Pavements. 45 8 days and roads are not opened for traffic until at least two weeks after the last concrete is put in place. The trunk roads are built 16 feet wide of concrete and secondary roads 15 feet, with a minimum width of 22 feet over all. These shoulders are usually built of limestone or gravel in two layers of 3 inches each and rolled Avith a 10-ton roller. This work is not started until the adjacent concrete is at least three weeks old. ''We do all work ourselves under the day labor plan/' says Mr. Hines, "and during parts of our busy season employ as many as 1,200 workmen; handle from 900 to 1,000 cars of materials a month and build a mile of road, in the aggregate, every three days. Ma- chinery plays an important part with us, as we do not believe that a man should be set at a task which a ma- chine can do as well or better. Stone, sand and cement are hauled from railroad sidings to the job by steam hauling engines or combination traction engines and rollers; graders, rooter plows and scarifiers are hauled in the same manner, doing the work of from 6 to 8 horses, more efficiently and more rapidly. Each con- crete gang uses about 15,000 gallons of water a day, which is pumped from the nearest available source. ''Two-inch pipe, with a tap every 400 feet, is laid along the road under improvement. Gasoline engines furnish the motive power and we have pumped water as far as six miles. Where we can find room along rail- road side tracks, we operate a Brown hoist, with a ton bucket for transferring stone and sand to our hauling wagons. Concrete is mixed in a mechanical batch mixer that travels under its own power, and from which a boom projects, capable of being swung in the arc of a semi-circle. Our men are housed and fed in 46 Concrete Roads and Pavements. lO CD O lO CD 00 CD O t- LO 1—1 O OS o 00 • t- CD o t- 00 u:) LO O CO t- t- O (M O C • O CD O Tt^ . • 00 lO C 13 O Oi "* <£ t- CO l« OO . Oi 00 IM tH . ■r-\ CD C^ CO ,H . a T— 1 lyD co'os • • O to 00 Tt^ t- IT o tH -^ t~ T- iH O -<*i t- • O tH t- Oi Oi ^ CO CO rH ■<*< LO -^ LO 00 o ■ O -* t- •<* CO c t- ■* O 1-H 00 Oi C- T-H T— 1 1 m O • OO CD lO 00 C t^ =i, o • 13 LO cq tH CD • o • • a '. '. a 6 is! V ;- ^ d *o •r-j d d a 4J be d • O) d o d 03 m o o '% <= o o f- — c c 03 d ams her bble nd . men 03 a 1 IT i se^ s a -1- c 0) c: PMo: a o jj ^ O CO U5 • OS U5 O t- «o • Oi • 00 Co' t-^ t> CO O ' ClTj5i6oioiL005Coe6i>co 00 00 C ee- «^ O . . 'CCCQMCQ H ties ft. ton ton bbl ton Quanti etc 2,400 1,337 456 17 1 lOeOt-OirHOOOO -OOIO-^O • (Si iHt- •COLOOStH oc ;Oo6ooJt^t^-* 'CDOOtH-^ t- c: tf •*-* .COt-COTH'^O'-H .LOC^aOlO t- ct o .Ttl0t-C5 • • rH 1-H CO C^ CO > e«- €/9- 4- CO m cc 03 s 1) +J +J ^J ri 'V .« CM • 00 oo" <=^ ■ tH CO irt <^ w- rH . T-l r-i •O • o -c o 1 C W2 iJ ^5l • 00 KD •■<* o 5 • o TJH .00 c CO 0) ^ o;^ M oo rfH • c- iH > < .^-^3" C-^ t-^ <^ '. ^ -^ ^c'S se- t-o oc- t~ • ^ CO o ;h ?os^ '^^ OO • 05 CO 00 > 6l • lOrfi oc^- oo- 1-1 IT c^ir OO CO CO COCO OlO 00 Cs 05(M T-l CO 01 lO_|>. oo^co (TQLO eoi> :. "^'^ rHtO > oj T-T i-T NC^T c coc- > . . . ^ ^ , ^' oS o +J ••-> 4-> •d g C-H i-«H «H «H — I O O «H O O o rQ 02 O) c O o in -r-l o>p 1^ '^^ (52) Concrete Roads and Pavements. 53 termined from a table, which gives the cost of the work on the concrete roads constructed during 1912. Having determined the cost per square yard for the two thicknesses given, and for the four lengths of haul given, the cost per mile for the concrete roadway of varying widths is determined by multiplying the number of square yards in a mile of road of the given width by the cost per square yard. The table also gives the cost of a mile of concrete road 6 inches thick and 10 feet wide, with 3 feet of macadam on each side of the concrete roadway. In computing this cost, the cost of the concrete roadway is determined as before ex- plained, and to that is added one-third of the cost of a mile of 12-foot macadam road. This cost of the macadam, alongside the concrete, is determined on the assumption that it is made two-thirds the thickness of a standard macadam road, and being one-half as wide, will therefore require one-third of the material and labor of a 12-foot macadam road. In the same manner the cost of a concrete road 12 feet wide, with 2 feet of macadam along each side, is determined with the assumption that the cost of the macadam will be one-sixth the cost of a standard 1 2-foot macadam road. The details on the various roads built of concrete during the year are as follows : Cliandlerville-Beardstown Road^ Chandlerville Township, Cass Cou7ity. This consists of a section of concrete road constructed over a particularly sandy piece of road just outside the village of Chandlerville. The work was done very largely by subscriptions and the cost data herewith given is made up on a basis of the day labor price for this subscription work, which in Costs of Concrete Boads Constructed in Illinois in 1912. Road. McLean. DeKalb. Spring- field. Carlin- ville. Amt. of pavement (sq.yds.) . . Thickness 5.000 6 in. 45 ft. V8 mile $1.02-1.06 29 bbl. 7.334 6 1/2 in. 12 ft. 1/2 mile 55 cents .31 bbl. 5,594 7 in. 18 ft. Vs mile $1,021/2 .29 bbl. 7,111 6 1/2 in. 16 ft. Sand 1% mile; stone, V2 mi. 98 cent*; Width Length ofi haul. Cost of cement Cement used per sq. yd .33 bbl. Cost of Iiabor and Supplies . Superintendence $ 140.00 $ 200.00 900.02 69.75 72.60 596.02 746.65 187.07 1,671.00 1.250.00 160.13 32.00 119.77 Vi'.ie 136.25 ? 202.00 2 32*. 4 4 211.38 603.50 644.25 383.75 1,622.01 1,551.17 206.74 119.19 18.33 $ 157.50 591 73 Excavation Shaping roadbed 307.41 108 70 Trimming shoulders and side roads Loading and hauling sand and stone, including re- handling 267.34 414.63 110.26 1.017.63 1,547.15 48.67 30.75 35.00 45.18 795 05 Mixing and placing cone. . . Watchman and misc. labor. Cost of sand and stone f.o.b. Cost of cement f.o.b 700.58 131.46 741.00 2,307.90 112.40 Reinforcing steel Coal and oil for mixer and miscellaneous supplies. Forms and other lumber. . . Filling - expansion joints 100.00 1 25.00 31.75 Carfares for men Pay for time of men coming and going 1 Total $3,964.02 $6,194.42 $5,794.76 $5,803.07 Cost per Square Yard for ^Labor and Supplies. Superintendence $0,028 $0.0273 $0.0361 $0.0220 0.1227 0.0095 b".64i5 0.0840 0.061 0.0153 Trimming shoulders and 0.0099 0.0378 Loading and hauling stone and sand. Including re- 0.053 0.083 0.0812 0.1020 0.1078 0.1150 0.1120 Mixing and placing cone. . . 0.0986 Watchmen and misc. labor.. 0.022 0.0255 0.0682 0.0184 Cost of sand and stone f.o.b. 0.204 0.2280 0.2897 0.1050 Cost of cement f.o.b 0.309 0.1700 0.2772 0.3246 Expansion joints 0.010 0.0218 0.0369 0.0156 Reinforcing steel 0.0140 Coal and oil for mixer and miscellaneous supplies.. 0.006 0.0044 0.0213 0.0034 Forms and other lumber. . . 0.007 0.0163 0.0033 0.0047 Filling expansion joints 0.010 Total $0,793 $0.8186 $1.0352 $0.8176 (54) Concrete Roads and Pavements. 55 many cases was more than the work was worth on account of its intermittent nature. The pavement constructed is a concrete roadway 16 feet wide and is 6 inches thick, gravel being used for the concrete. The following table is an itemized statement of the cost of this work: Amount of pavement laid 1,470 sq. yds. Thickness of pavement 6 inches Width of pavement 16 feet Length of haul for materials i/^ mile Cost of cement per barrel $1,13 and $1.20 Amount of cement per sq. yd. of pavement. . . 0.31 bbl. Cost of Labor and Supplies. Superintendence $ 50.00 Excavation (donation, value estimated) 71.73 Shaping road bed 29.75 Loading and hauling stone and gravel 173.21 Mixing and placing concrete 155.08 Cost of sand and stone 370.85 Cost of cement 553.03 Total $1,403.65 Cost Per Square Yard for Labor and Supplies. Superintendence $0,034 Excavation (donation, value estimated) .048 Shaping road bed .020 Loading and hauling stone and gravel .118 Mixing and placing concrete .105 Cost of stone and gravel .257 Cost of cement .378 Total $0,960 Sycamore-De Kalh Road, De Kalh Township, De Kalh County. The coimtry is fairly level, and only a small amount of earth work was necessary. The soil is a black loam clay, and the road was well drained. The concrete roadway was made 12 feet wide and 6^2 inches thick, with macadam shoulders 2 feet wide on each side of the concrete roadway. The concrete wa^ 56 Concrete Roads and Pavements. made of gravel and sand which was purchased in the market, and the cost of the entire improvement was paid from the regular road and bridge fund. A part of this road was reinforced with %-inch square twisted 10-foot bars placed crosswise of the pavement, and a part of the road was reinforced with ISTo. 26 A wire mesh made by the American Steel & Wire Company. The mesh is made up of No. 6 wire with 2-inch mesh, and was in strips 34 inches wide, which were laid crosswise of the road, overlapping about 2 inches. Beginning with the section ending at station 27 + 45 and continuing to the section ending at station 11+65, the reinforced sections alternate with plain con- crete sections as follows: The sections are numbered at the edge near the expansion joint and each section is the part of the pave- ment between two expansion joints. The various sec- tions follow each other in the following order and are numbered as here given: 1^0. 1. Reinforced crosswise with %-inch bars 2 feet center to center, 12 sections. ISTo. 2. Reinforced crosswise with %-inch bars 4 feet center to center, 12 sections. ISTo. 3. Plain concrete, 12 sections. No. 4. Reinforced with No. 26 A wire mesh, 4 sections. ^ The mesh reinforcement cost $1.84 per square of 100 square feet. The bar reinforcement cost 2 cents per pound, f. o. b. Chicago Heights, or 16.8 cents per bar 10 feet long at De Kalb. The following table is an itemized statement of the cost of this work : Concrete Roads and Pavements. 57 Amount of pavement laid 7,334 sq. yds. Thickness of pavement 6^^ inches Width of pavement 12 feet Length of haul for materials ^2 mile Cost of cement per barrel $0.55 Amount of cement per sq. yd. of pavement 0.31 bbl. Cost of Labor and Supplies. Superintendence % 200.00 Excavation 900.02 Shaping road bed 69.75 Trimming shoulders and side roads 72.60 Loading and hauling sand and stone, including re- handling 596.02 Mixing and placing concrete 746.65 Watchman and miscellaneous labor 187.07 Cost of sand and stone f. o. b. DeKalb 1,671.00 Cost of cement f. o. b. DeKalb 1,250.00 Expansion joints 160.13 Reinforcing steel (bars, $294.00; mesh, $42.93) 336.93 Coal and oil for mixer and miscellaneous supplies. . . . 32.00 Forms and other lumber 119.77 Car fares for men 51.16 Pay for time of men coming and going 138.25 Total $6,531.35 Cost Per Square Yard for Labor and Supplies. Superintendence $0.0273 Excavation 1227 Shaping road bed 0095 Trimming shoulders and side roads 0099 Loading and hauling stone and sand, including re- handling 0812 Mixing and placing concrete 1020 Watchman and miscellaneous labor 0255 Cost of sand and stone f. o. b. DeKalb 2280 Cost of cement f. o. b. DeKalb 1700 Expansion joints (materials only) 0218 Coal and oil for mixer and miscellaneous supplies 0044 Forms and other lumber 0163 Total $0.8186 Peoria Road, Springfield Township, Sangamon County. The soil at the north end is black loam, and farther along clay and sandy soils are encountered. The 58 Concrete Roads and Pavements. road leads through rolling country, and a considerable amount of excavation was found to be desirable. The construction work began during the fall of 1912, and about one-half mile of pavement was laid. The roadway is gravel concrete 18 feet wide, 8 inches thick at the middle and 6 inches thick at the edge. On the section completed, armored expansion joints were used, but on the section to be built in 1913, it is planned to use creosoted block expansion and plain expansion joints filled with asphalt pitch. The following table of costs applies to the work which was completed in the fall of 1912. A considera- ble amount of material was on hand at the close of the season, to be carried over and used in 1913 : Amount of pavement laid 5,594 sq. yds. Thickness of pavement 7 inches Width of pavement 18 feet Length of haul for materials % mile Cost of cement per barrel. ^IMVz Amt. of cement used per sq. yd. of pavement. . 0.29 Cost of Labor and Supplies. Superintendence .$ 202.00 Shaping road bed 232.44 Trimming shoulders and side roads 211.38 Loading and hauling sand and stone, including re- handling 603.50 Mixing and placing concrete 644.25 Watchman and miscellaneous labor 383.75 Cost of sand and stone f. o. b. Springfield 1,622.01 Cost of cement f. o. b. Springfield 1,551.17 Expansion Joints 206.74 Coal and oil for mixer and miscellaneous supplies... 119.19 Forms and other lumber 18.33 Total .$5,794.76 Cost Per Square Yard for Labor and Supplies. Superintendence $0.0361 Shaping road bed 0415 Trimming shoulders and side roads 0378 Loading and hauling sand and stone, including re- handling 1078 Concrete Roads and Pavements. 69 Mixing and placing concrete 1150 Watchman and miscellaneous labor 0686 Cost of sand and stone 2897 Cost of cement 2772 Expansion joints 0369 Coal and oil for mixer and miscellaneous supplies 0213 Forms and other lumber 0033 Total $1.0352 Town Square, Mt. Hope Townsliip, McLean County. In 1907 a macadam road was constructed in the village of McLean extending from the town limits up to the town square, the town square itself not being improved. This town square consists of a triangular park surrounded by a roadway, along which are the principal business houses of the village. The improve- ment consists of a concrete roadway 45 feet wide, with a total area of 5,000 square yards. The concrete was made 6 inches thick and was constructed from gravel, to which was added a small amount of Joliet crushed stone. The following table is an itemized statement of the cost of this work : Amount of pavement laid 5,000 sq. yds. Thickness of pavement 6 inches Width of pavement 45 feet Length of haul for materials Vs mile Cost of cement per barrel $1.02 and $1.06 Amt. of cement used per sq. yd. of pavement. 0.29 bbl. Cost of Labor and Supplies. Superintendence $ 140.00 Shaping road bed 307.41 Loading and hauling sand and stone, including re- handling 267.34 Mixing and placing concrete 414.63 Watchman and miscellaneous labor 110.26 Cost of sand and stone f. o. b. McLean. . ; 1,017.63 Cost of cement f. o. b. McLean 1,547.15 Expansion joints 48.67 Coal and oil for mixer and miscellaneous supplies.., 30.75 60 Concrete Roads and Pavements. Forms and other lumber 35.00 Filing expansion joints next curbs 45.18 Total $3,964.02 Cost Per Square Yard for Labor and Supplies. Superintendence $0,208 Shaping road bed .061 Loading and hauling stone and sand, including re- handling .053 Mixing and placing concrete .083 Watchman and miscellaneous labor .022 Cost of sand and stone .204 Cost of cement .309 Expansion joints .010 Coal and oil for mixer, and miscellaneous supplies.. .006 Forms and other lumber .007 Filling expansion joints next curbs .010 Total $0,793 Burhe Lane Road, Carlinville Township, Macou- pin County. The soil is a black loam, and the road was fairly level, but was thickly shaded and had been one of the worst roads in the community on that ac- count. It had been filled in places with stone, brick and cinders, making what little excavation had to be done, expensive. The improvement consists of a con- crete roadway 16 feet wide and 6% inches thick. Crushed stone for the concrete was furnished from the Southern Illinois Penitentiary and sand was hauled from a creek west of Carlinville. From the C. & A. tracks to the culvert at about station 8, the middle of the road was reinforced by %-inch square twisted bar 6 feet long, running cross- wise and placed one foot from center to center. This was made necessary by a newly filled sewer trench under this section of road. The following table is an itemized statement of the cost of this road : Concrete Roads and Pavements. 61 Amount of pavement laid 7,111 sq. yds. Thickness of pavement 6V2 inches Width of pavement 16 feet Length of haul for materials 16 feet Sand 1^/^ miles Stone li^ miles Cost of cement per barrel f. o. b. Carlinville. ... 98 cents Amt. of cement used per sq. yd. of pavement. . . . 0.33 bbl. Cost of Labor and Supplies. Superintendence $ 157.50 Excavation 591.73 Shaping road bed 108.70 Loading and hauling sand and stone, including re- handling 795.05 Mixing and placing concrete 700.58 Watchman and miscellaneous labor 131.46 Cost of sand and Stone f. o. b. (stone freight only, sand free) 741.00 Cost of cement f. o. b Carlinville 2,307.90 Expansion joints 112.40 Reinforcing steel 100.00 Coal and oil for mixer, and miscellaneous supplies. . . 25.00 Forms and other lumber 31.75 Total $5,803.07 Cost Per Square Yard for Labor and Supplies. Superintendence $0.0220 Excavation 0840 Shaping road bed 0153 Loading and hauling stone and sand, including re- handling 1120 Mixing and placing concrete 0986 Watchman and miscellaneous labor 0184 Cost of sand and stone f. o. b. (sand free at pit) 1050 Cost of cement f. o. b. Carlinville 3246 Expansion joints 0156 Reinforcing steel 0140 Coal and oil for mixer, and miscellaneoui supplies... .0034 Forms and other lumber 0047 Total $0.8176 (62) CHAPTEE Y. Othek Examples of Co]s^crete Eoads. MilivauJcee County Roads. Milwaukee County, Wisconsin, started in 1912 on the construction of a com- prehensive system of concrete roads, under the super- vision of Mr. H. J. Kuelling, formerly with the Wis- consin State Highway Commission. The work is all one-course work and is laid in widths of 16 to 18 feet with an average thickness of 7 inches. The specifications for the most part provide for a crown of % inch to a foot, which in some cases will be carried into the sub-grade. On the work done during 1912 the making and placing of the concrete was done by contract and in some instances the grading as well; in some cases, however, the commissioner did his own grading by force account, and all culverts are being made by a gang of men under his direct control. On the contract work the county furnished all ma- terials, the cement being delivered to the job by the dealer, and the contractor being required to haul his stone and gravel. Water is also supplied by the county and has furnished one of the difficult problems of the construction of the roads. The difficulty of securing suitable w^ater as needed has led the county to buy all its water from the city, piping it out to the jobs through 2-inch pipes. If necessary, pumps are used to secure sufficient pressure. The specifications state that concrete shall consist of one part cement, two parts sand and four parts stone, (63) 64 Concrete Roads and Pavements. the parts determined by volume. In regard to tlie ma- terials, however, the commissioner has done some ex- perimenting and an effort vt^as made in some cases to secure a pit run material which would have approxi- mately the correct proportions of sand and gravel with- out grading. The plan at present is to screen the gravel as it comes from the pit through a %-inch screen, all below this size being used for sand and above this size up to 2% inches being considered gravel. These are then combined in proportions of 2 to 4, the combination being effected in some cases at the pit and in other cases on the job. The specifications require that con- crete shall be mixed in mechanical batch mixers. As a result of this experiment, Mr. Kuelling says that two of the biggest mistakes anyone can make in this class of work are : First, to take the gravel directly from the pit, and second, the use of dirty materials. The pit run gravel showed a great variation, and almost all of it with an excess of sand, making a larger amount of cement necessary than where the materials are care- fully graded. The county has now bought rights to cer- tain gravel pits,, and has put in screening plants, so that materials are carefully screened, cleaned and graded. The roads have scarcely any tendency to steep grades, but the disposition of the commissioner is to keep the grade down to 4 per cent in any case. The method of construction is, in the first place, to stake a 2x7 inch plank at the outer edge of the pro- posed road, the upper edge of the plank to conform with the finished grade of the work. The concrete is then placed in position ; and while the specifications call for tamping, the mix used is so wet that very little tamping is necessary. Two men are employed on each job whose Concrete Roads and Pavements. 65 special duty it is to strike off the surface with a strike board, this board having a curvature corresponding to the crown of the road and its ends resting on the planks at the sides. Under extreme heat, or when overtaken by rain, the work is covered with canvas or other suit- able means and is thus protected until it takes its initial set. After a number of hours it is covered with a light layer of earth, approximately one inch thick, and is sprinkled each day for five days. The earth covering is removed in from 10 to 14 days. Expansion joints are put in transversely every 25 feet. These expansion joints consist of two Baker dividing plates, having shear members which extend into the concrete and anchor them firmly to it. Between the two plates is placed two layers of tar felt in 7-inch width, thus making the joint the full depth of the road. The work of the new Chicago road was somewhat out of the ordinary, because of the fact that it had to be done on both sides of an inter urban railway track. This complicated the work, as the track had to be kept open for the passage of cars, and it was neces- sary to find storage room for materials on contiguous private property. The mixer also had to be located at such points as could be found convenient and longer hauls of the concrete were made than would otherwise be allowed. The equipment of the plant consisted of a Smith %- yard mixer mounted for end discharge, and delivering the concrete into Briggs carts, in which it was conveyed to the point of deposit. The mixer aimed to cover about 1,000 feet to a set-up, making the longest haul 500 feet in each direction. Up to a haul of about 300 feet, two of the Briggs carts were used, while on longer (66) Concrete Roads and Pavements. 67 hauls a third one was called into requisition. The ma- terials Avere Avheeled to the mixer by wheelbarrows from stock piles near at hand and dumped into an automatic loader. Six men were employed on Avheeling, three men on the mixer, including the engineer, five men placing con- crete, three men on the carts, one man making up and placing joints, and two men working ahead cleaning up the roadway and j^lacing forms. This gang covered 400 to 450 square yards per day. The work on the Janesville road was of the stand- ard type, 18 feet wide. Here a different method of con- struction w^as employed, the materials being delivered in the middle of the road and thrown directly into the loading hopper of the mixer and in turn discharged by the mixer directly at the point of deposit. For this W^ithdrawing the Stakes W^hich Hold the Joints. 68 Concrete Roads and Pavements. purpose a Chain Belt mixer was arranged on trucks for end discliarge and provided with a swinging steel chute so that it distributed concrete over the entire width of the roadway. Moves of about 5 or 6 feet were made at frequent intervals. The crew on this work consisted of 17 laborers, one engineer and two foremen. At the time these notes were taken the gang was progressing at about the rate of 100 lineal feet per day. The work on the Kilbourn Road was also 18 feet wide and the methods of construction were similar to those employed on the Chicago Road, the mixing plant being stationary and the concrete being delivered to the work in Briggs %-yard concrete carts, with a limit of haul of 400 feet. The crew consisted of 8 men wheeling and shovel- ing, 3 men on mixer, 4 men spreading and laying, 3 men on carts, 2 men on joints, 4 men unloading carts, 1 foreman, and boy. These roads are costing in the neighborhood of $1.00 per square yard, exclusive of the grading, dis- tributed as follows : Cement $0.33 Gravel and stone 16 Labor and hauling .43 Joints ; 06 Inspection and water 02 Total $1.00 At Winona, Minn. In 1912 Winona County, Minnesota, let contracts for 16 miles of concrete roads, at a cost of $116,000. This price was about $10,000 less than the lowest bid on the same roads in macadam, by the same bidders, and figures out to about $7,250 per mile, although the grading varied to such an extent as Concrete Roads and Pavements. 69 to make an average figure of little value. The specifica- tions provide that the sub-grade shall be brought to a firm, unyielding surface where fills are made, by rolling each 6 inches of fill. x\ll soft or spongy spots, vegetable or perishable matter is removed and replaced by the same material as that of which the sub-grade is com- posed. When heavy clay soil is encountered it is pro- vided that the sub-grade shall be excavated 4 inches be- low grade and shall be filled with crushed rock or gravel rolled to a thickness of 4 inches. The concrete roadway proper is laid on the center line of the road to a width of 8 feet and a thickness of 6 inches, with a cro^vn of 1 inch. The concrete is laid in sections 35 feet in length, separated by %-inch ex- pansion joints, these extending through the entire thick- ness of the slab and being filled after construction with a bituminous filler. The expansion joints are formed by three strips of steel, cut to the size and shape of the cross-section of the road, and with projections at the ends to permit of their removal. After the concrete has set the middle strip is first removed, after which the other strips can readily be taken away. The surface of the roadway is finished with a wood float, and where the grades exceed 4 per cent the surface is grooved with a grooving tool in both direc- tions, the longitudinal grooves being 10 inches apart and the transverse grooves 3 inches apart. The grooves are %-inch wide and %-inch deep. The specifications provide that the sand shall be graded up to % inch and shall not contain clay or loam in excess of 4 per cent. The gravel provided for is com- posed of hard, dry pebbles not larger than 1% inches nor smaller than % inch. YO Concrete Roads and Pavements, The materials are pilt onto the road in the propor- tions of 1, 2 and 4, the sand and gravel being measured loose in measuring boxes and a sack of cement being considered equal in volume to one cubic foot. The specifications call for a mixture of such con- sistency that it will quake slightly when tamped, but not so thin that it cannot be troweled to the required cross section. The mixing is done by a Koehring street paving mixer of the self -tractive type, carrying a swing- ing boom which covers the entire width of the roadway for the delivery of the concrete. The machine is equipped with an end-loading bucket holding the full capacity of the drum, with a water measuring tank which supplies the proper amount of water to each batch, and a water tank mounted on the frame to supply water for the steam boiler. This machine discharges at the rear and is provided with traction drive for moving it along the roadway so that it may always be located just at the point where concrete is to be placed. The specifications provide that the contractor shall wet and tamp the sub-grade to a proper form imme- diately before the concrete is placed and that the con- crete shall be placed to full width and thickness of the roadway at one time and well tamped and struck off with a template and floated to the entire cross-section with wood floats. After the concrete is set, it is covered with about one inch of wet earth and gravel and is kept free from travel for a period of two weeks. On one side of the concrete roadway is a shoulder of gravel which is rolled to a thickness of G inches at the edge of the concrete, 4 inches at a point 4 feet Concrete Roads and Pavements. 71 away, and is feathered off to a point 6 feet from tlie edge of the concrete. Where it is necessary to carry flood waters over the roadway, especially on side hills, the concrete is placed the fnll width of the roadway in the form of a ''dip," somewhat similar to the old-fashioned ''thank-you- ma'am" of the dirt road. This dip has a depression of 6 inches to 10 feet ont of grade line, and is given a slight skew to the lower side of the road so as to carry off the water more readily. The qnantity of concrete used is 14.81 cubic yards per 100 feet, or 782 cubic yards per mile. The contract price as given includes all grading, of which there is over 40,000 cubic yards, also culverts and a small amount of concrete and rip-rap retaining walls. In a paper before the Minnesota Society of En- gineers and Surveyors, Mr. O. B. Leland, engineer in charge of the Winona work, stated: ''The grading is costing on an average a little over 40 cents a yard. The concrete culverts cost about $50 each for 18-inch, $65 each for 24-inch, $85 for 30-inch, and $105 for 36-inch, placed in the road. The average cost of grading per mile, including culverts, is $1,500. The macadam costs about 25 cents per lineal foot of road, and the concrete 90 cents per lineal foot of road. We are get- ting 16 miles of good road for $116,000." An Experimental Road in California. An experi- mental concrete road, 3,000 feet long and 18 feet wide, was constructed in the fall of 1912 between Sacra- mento and Riverbank, Cal., passing through the River- bank subdivision of the West Sacramento Company. The company has large holdings in this vicinity, in the T2 Concrete Roads and Pavements. development of which the road problem led it to ex- periment with ten various sections of concrete pave- ment to determine its applicability to local climatic, traffic and subgrade conditions. The engineers also wished to determine the most economical design. It is believed the comparatively uniform temperatures in California will minimize to a large extent expansion and contraction difficulties. The details as here given are taken from Engineering Record of March 8, 1913. On the western half of the roadway the sub-grade material is a heavy clay loam soil, resembling an adobe. The eastern half of the slab was constructed over an old macadam roadway. The subgrade was excavated and trimmed to the required grade and crown. It was then thoroughly compacted by sprinkling and rolling with an 8-ton roller. All portions of the old macadam road in fill were well tamped. In all cases the subgrade was well moistened just previous to placing the con- crete to prevent abstraction of water from the concrete. All work was given a crown by sloping the surface from the center to each side of the roadway at the rate of % inch per foot. Local experience with other types of pavement has led to a standardization of this fea- ture. Longitudinally the roadway is practically level. Four of the sections were reinforced with a light wire mesh having a cross-sectional area less than 0.1 per cent of the area of the concrete. While this is sufficient to reinforce the slab against temperature and shrinkage stresses, it was thought that it might prove valuable in holding the road intact. Rectangular and triangular mesh reinforcement of the American Steel and Wire Company and the Clinton Wire Cloth Com- pany was used. Concrete Roads and Pavements. 73 Four types of expansion joints were experimented with. In the first, lines of oiled surfaces were spaced at 10, 20, 30 and 40-foot intervals squarely and diag- onally across the pavement. Tar-paper joints were laid 10 and 20 feet apart on square and diagonal lines. In another section %,-inch spaces were filled with bitumen at intervals of 25 and 40 feet on square and diagonal lines, transversely with the pavement. A fourth type consisted of %-inch spaces at 30-foot inter- vals, squarely across the pavement, with the edges pro- tected by soft steel plates 4 inches wide and held in place by anchor bolts. A section 217 feet long was laid without expansion joints. Various types of finished surface were used. These included roughening with wire brooms, pitting by an embossed tamper, checkering and grooving with checks 6 inches square, plain concrete, sanding and covering the surface with a A-inch coat of bitumen and ^ato- raas rock screenings. Concrete was mixed in a %-yard gasoline engine- driven Ransome mixer on the sidewalk area alongside the road and wheeled to place in 10 cubic foot buggies. At each position of the mixer about 300 feet of road were laid. Three classes of fine aggregate were used: First, Sacramento River sand, dredged near the site of the work, having very fine, much rounded quartz grains. It contains a considerable proportion of mica flakes, but very little sediment. Second, Yuba River sand, dredged from the Yuba River at Marysville, having medium- sized quartz grains, somewhat rounded. It contains little mica, but small amounts of sediment and small balls of mud. Third, Natomas fine crushed rock, vary- Concrete Roads and P^mienisT O o ^ d 0)0)04 bo o) -a > 0) O ^3 P fl 03 C) g « o) O) *3 00 O) O 0> rj «§^ d M g ill O) O) o o ft 0» ^ o>,2 ^ ^ CO -M U) "5 *3 XJ o» ^ 0) ;h s S CO 73 Q^ c rt c3 CO o d .9 -M s ;^ H >>d.9 d t-^ <^ ^ ftco n rt P o •" d -d ft o> CO +-> o o» 5^ |d^ d .s d ^ :3 o ^ o ^ o o 0) 1—1 0) CO be d d =^3 ^d.9 to to CO tH tH iH saqoui ui (x> :j88jl UI q;Su9T O O O o H OGJ^ •^ O) ,| 'd -^ ^ -4 cj -d 'cs O) Oi ^ ,d 02 d fog m t- o -M to bo d-d fl-d 2 O) 2 O) o 5 beg bog-S O f-, O "" ^ bb d ^ d bfi ed d irJ ■fi d o !h ;d O) -M CO . 'C (^ 0) d t- a 0) d 2^ • d t-

;^ CD lO ;^ i TtH rj^ LO^^ lO (M C^ W C<> 1/5 <£> t- 6* for spans from 3ft' "" Uac 2''4' for heights 3ffand undo 4'«4' for heiqhfs fronn 3f> INLtT END rOBM Use oufside forms where earfh cannot- bftctrt- smooVh. Use 2'plank(no+ nailecj)for flooring. Use I'or li" lurnbsr for wings and inside forms. PLAM OF F-OF2MS o"^ YPICAL. BOX CUL-VEIISTS SBA,NS fc. hElOMTS "' Vltre 'these torois OUTLET END rOBM crecr^eo/ 2" y//7(tn earfh /Is u3Gd / For oa^^/'c/'(^ forms i 0, 4^ X X. IV) HEIOHT ^P/}N ^ ^ ^^ ^ ^ ^. to to to Oo ^ THICKNE65 fl&uTMmr ^ ^. ^ <^ ^x -Nl Oa ^. N r ^^ ^; -; v ^ ^ L£/YOTM 1^^ ^ *^^ 0-^ Vi ^ Ki K ^ ^ % * \ ^1 t Nt^ t \ $ ft TOP Oi Hi I a. \ 1: t (\K t MK r Borh. . , • • ' • ■ * DOWELS ^ 1 K ^ ^^ WEI&HT LHFT. 1 C) (J4 5?i 1 1 ^ § ^ ^ .^ U co/fcefTE un.FT I .•NJ E ^ ^ <> CONCeiTE 1 % 5; ^ 1 ^ 0, JTEEL 5 ^ Si !5> 1 CO/^aDE 1 1 Is i ^ 4^ ^ Oi ^ ^ JTEEL (171) 172 Concrete Boads and Pavements. of a hard, black nature that was hard trimming. Water for mixing had to be hauled two miles. Sand gravel was used for aggregate in the concrete. The gravel contained a slight excess of sand and worked up in the proportions given. Mixing was done by hand with negro labor. Twisted square steel bars were used for reinforcing. Labor. Foreman, 40 hours @ 25c $10.00 Culvert excavation, 9 cubic yards @ 80c 7.20 Labor on forms 14.00 Mixing and placing, 120 hours @ 15c 18.00 Hauling water, 20 hours @ 30c 6.00 Cutting and placing steel, 10 hours @ 15c 1.50 Cleaning up and removing forms, 10 hours @ 15c. 1.50 $58.20 50% salvage on forms 7.00 $51.20 Moving on and off job 10.00 Total labor at culvert $61.20 Material (Laid Down at Culvert). Cement, 26 barrels @ $1.80 $46.80 Hauling cement, 12 1/^ hours @ 30c 3.75 Gravel, 18i/^ cubic yards @ $1.10 f. o. b. cars Ennis, Texas 20.35 Hauling, l^Vz cubic yards, 46 hours @ 30c (75c per cubic yard) 13.80 Steel, 1,072 pounds @ 2i^c 26.80 Hauling steel, 2 hours @ 30c 60 Lumber, 1,000 feet B. M. @ $25.00 25.00 Hauling lumber, 3 hours @ 30c 90 $138.00 75% salvage on form lumber 18.75 Total cost of material at job 119.25 Total cost of job $180.45 Cost per cubic yard of concrete in place, exclusive of culvert excavation 9.37 Cost per cubic yard of concrete in place, exclusive of excavation and steel 7.85 Concrete Roads and Pavements. 173 The quantities were as follows : 14^2 cubic yards of 1:3:5 concrete; 4 cubic yards of 1:2% :4 concrete; 432 pounds of %-incli steel; 640 pounds of V2-incli steel, and 1,000 feet B. M. of lumber. Luten Truss. On page 174. is sllo^^^^l a design for small bridges and culverts using a built-up reinforce- ment known as the Luten truss. It is intended for slab bridges of spans up to 20 feet and for girder bridges of greater length. The steel is in the form of a rigidly constructed unit clamped together with locked wedges. It is set directly on the forms and the concrete poured around it. Size of Culverts. A number of formulas, designed to aid in estimating the size of culverts, and based on the considerations stated, have been proposed. The most common of these is Myer's formula, which states the re- lation between the drainage area as follows : The required area of waterway in square feet is equal to the square root of the drainage area in acres, multiplied by a number varying from 1 to 4, depending on the character of the watershed. For slightly rolling- ground, this number is taken as 1 ; for moderately hilly ground, at 1^2 or 2 ; and for steep, rocky ground, at 4. For a drainage area of 40 acres, this would mean that level or slightly rolling ground would require about 6 square feet, which is a 2x3-foot box, or a 36-inch pipe ; if moderately hilly, it would require about 12 square feet of opening, which is a 3x4-foot box or a 48- inch pipe ; or, if the ground is very steep and rocky, from 25 to 30 square feet, meaning that a 5x6-foot cul- vert or a 6-foot pipe will be required. There are other similar formulas, but all are valu- able simply as guides to the judgment in forming an opinion as to the reliability of any information gathered (174) Concrete Eoads and Pavements. 175 from local sources. It can readily be seen that the selec- tion of the constant multiplier is left entirely to one's judgment, and this makes the result obtained by the use of the formula almost wholly a matter of opinion. A very important thing to be taken into account is the height of the fill over a culvert. If a culvert dis- charges under a head, the discliarge is increased very rapidly as the head increases ; so that if the fill is deep, and the water can be dammed to some extent, it is safe to use a smaller culvert than Avould be safe Avith a shal- low fill. The shape of the opening in a culvert is of little significance, provided that the area of the opening is sufiicient. For the larger sizes, it certainly is easier to build the culvert rectangular in form, Avith a fiat top, principally because of the fact that the forms can be built more easily, and Avith less cutting of lumber. There is added advantage in that for any giA^en span a rectangular opening Avill give more AvaterAvay than an arched opening. Also the Avidth of the opening re- mains constant, regardless of the height to AAdiich the Avater may rise. It is usually an advantage in the larger culverts to liaA^e a separate foundation for each side Avail, but in the smaller culverts the Avhole bottom should be paA^ed, as in this Avay the foundation is protected from scouring. Especial care should be taken to have the cuh^ert dis- charge in such a Avay that the loAver end Avill not be undermined. The forming of small culverts is a matter of some difficulty : though not so much the forming itself as the removal of the form after the culvert is set. Mr. M. W. Torkelson, bridge engineer for the Wisconsin HigliAvay Commission, states that he has seen numerous small 17^ Concrete Roads and Pavements. culverts with a portion of the form lumber remaining fast in the culvert. This is a serious condition, because it is apt to cause the culvert to become filled with trash, effectually stopping the flow of water through the cul- vert and rendering it liable to a washout. He believes that much of this trouble could be obviated by building the forms less tight, and covering open spaces in the forms with building paper fastened to the forms with small tacks. It is also thought that the boards compos- ing the forms could be leveled in such a way as to make their removal easier. Also, no culvert should ever be less than 18 inches square if there is room to permit. In the building of these smaller culverts, the cost of forming is one of the most important items. The amount of concrete required is very small. The labor of excavation, etc., is also usually slight, but the trouble of forming and of removing forms is considerable. The Avriter believes that these small culverts can best be built with some permanent forms which can be easily set up and conveniently removed as soon as the concrete has set reasonably well, and then used at another point. It seems certain that such a form can best be built of metal, especially for a culvert with a circular opening. There are several such forms on the market. Mr. Torkelson, quoted above, says that it is the practice of the Wisconsin Highway Commission to use concrete wherever possible. It believes that where ma- terials are reasonable in price, and the cost of founda- tion work not too great, that concrete is the most eco- nomical material. It recommends the following general rule for design : For the shorter spans up to about 25 feet, flat slab construction is recommended ; for spans from 25 to 40 feet, the through girder or arch type; and for greater spans, arches. CHAPTER XIII. Sidewalks, Cuebs and Gutters. This is a subject closely allied to the general topic treated in this volnnie, and yet one on which we need say little more than to call attention to the standard specifications of the Xational Association of Cement Users, printed in Appendix K and Appendix L. Concrete has come to be the standard material for these purposes, and its utility is never questioned. In very few cities indee-d is anything else now used for the construction of sidewalks, curbs and gutters. In a few smaller places the plank sidewalk is still allowed, but even in these towns most of the residents build with concrete of their own accord, and the city councils are rapidly seeing the wisdom of this course and are one by one making the concrete sidewalk mandatory. In isolated cases, too, stone curbing is used; but they are so infrequent as merely to emphasize the gen- eral use of concrete for this purpose. Concrete for these purposes has everything in. its favor. It is long lived, pleasant to the tread, sightly; and what is perhaps more important from the stand- point of city economy, it does not become dilapidated, causing accidents and involving the city in countless damage suits, as is the history of the plank walk. Tak- ing all these things into consideration, concrete is by far the cheaper material in the end. A number of years ago many people hesitated to put down concrete walks because of the fear that they (177) 178 Concrete Bonds and Pavements. would not get good workmanship. This is no longer true. The method for the laying of such walks has become standardized, as embodied in the specifications given in the Appendix, or in the specifications of pro- gressive cities;- and knowledge in regard to .concrete has become more widely disseminated, so that almost any reputable contractor can ])e relied upon to do in- telligent and satisfactory work. It is also true that improvements in methods, the gradual reduction in the price of cement, and the in- crease in competition in this line of work, have brought the price down considerably ; and with lumber con- stantly rising in price, a concrete walk no longer looks like an extravagance to the ordinary property holder as compared with plank. The perfection of metal forms for sidewalk, curb and gutter work is perhaps one of the most important developments in this branch of the industry within recent years, and is calculated to add still further to standardization and economy. Sidewalks, like jDavements, may be built in either one or two courses, the latter method being the one in most general use. It is probable, however, that the one- course walk is destined to grow in favor. APPEXDTX A. SPECIFICATIONS OF NATIONAL ASSOCIATION CEMENT USERS- ROADS AND PAVEMENTS. Materials. 1. Cement. — The cement shall meet the requirements of the Standard Specifications for Testing Materials, and adopted by this Association (Standard No. 1). 2. Fine Aggregate for Concrete. — Fine aggregate 'shall consist of sand, crushed stone or gravel screenings graded from fine to coarse and passing, when dry, a screen having 1/4 -inch diameter holes; shall be preferably of silicious ma- terial, clean, coarse, free from dust, soft particles, loam, vegetable or other deleterious matter, and not more than 3 per cent shall pass a sieve having 100 meshes per linear inch. Fine aggregate shall be of such quality that mortar com- posed of 1 part Portland cement and 3 parts fine aggregate, by weight, when made into briquettes, will show a tensile strength at least equal to the strength of 1:3 mortar of the same consistency made with the same cement and Standard Ottawa sand. In no case shall fine aggregate containing frost or lumps of frozen material be used. 3. Aggregate for Wearing Course. — The aggregate shall consist of screened gravel or stone screenings from granite or other close-grained, durable rock, sufficiently hard to scratch glass, free from loam or other deleterious matter, mixed in the proportion of 3 parts passing a i/^-inch ring and retained on a screen having l^-inch diameter holes, and 2 parts passing a screen having i/4-inch diameter holes, and retained on a screen having 50 meshes per linear inch. In no case shall aggregate for wearing course containing frost or lumps of frozen material be used. 4. Coarse Aggregate for Concrete. — Coarse aggregate shall consist of inert materials, such as stone or gravel, graded in size, retained on a screen having i^-inch diameter holes; shall be clean, hard and durable, free from dust, vegetable or other deleterious matter, and shall contain no soft, fiat or elongated particles. In no case shall coarse aggregate containing frost or lumps of frozen material be used. The maximum size of the coarse aggregate shall be such as to pass a li/^-inch ring. 5- Natural Mixed Aggregates. — Natural mixed aggregates shall not be used as they come from deposits, but shall be (179) 180 Concrete Roads and Pavements. screened and remixed to agree with the proportions specified. 6- Sub-base. — Only clean, hard, suitable material, not exceeding 4 inches in the largest dimensions, shall be used. 7. Water. — Water shall be clean, free from oil, acid, alkali or vegetable matter. 8. Coloring. — If artificial coloring matter is required, only mineral colors shall be used. 9. Reinforcing Metal. — The reinforcing metal shall meet the requirements of the Standard Specifications for Steel Reinforcement adopted March 16, 1910, by the American Rail- way Engineering Association. Sub-Grade. 10. Section.- — The sub-grade shall have a rise at the cen- ter of not more than 1-lOOth the width of the pavement. 11. Depth. — (a) The sub-grade shall not be less than 12 inches below the finished surface of the pavement. (b) The sub-grade shall not be less than 6 inches below the finished surface of the pavement. 12- Preparation. — All soft and spongy places shall be re- moved and all depressions filled with suitable material which shall be thoroughly compacted in layers not exceeding 6 inches in thickness. 13. Deep Fills. — When a fill exceeding 1 foot in thick- ness is required to bring the pavement to grade, it shall be made in a manner satisfactory to the engineer. 14." Drainage. — When required, a suitable drainage sys- tem shall be installed and connected with sewers or other drains indicated by the engineer. (Note. — When a sub-base is required, eliminate Paragraph 11-b. When sub-base is not required, eliminate Paragraphs 6, 11-a, 15 and 16. Unless 11-a is eliminated, 11-b is void.) 15. Thickness. — On the sub-grade shall be spread a ma- terial as hereinbefore specified, which shall be thoroughly rolled and tamped to a surface at least 6 inches below the finished grade of the pavement. 16. Wetting. — While compacting the sub-base, the ma- terial shall be kept thoroughly wet and shall be in that con- dition when the concrete is deposited. Forms. 17. Materials. — Forms shall be free from warp, and of sufficient strength to resist springing out of shape- 18. Setting. — The forms shall be well staked or other- wise held to the established lines and grades and their upper edges shall conform to the established grade of the pavement. 19. Treatment. — All wood forms shall be thoroughly wetted and metal forms oiled before depositing any material against them. All mortar and dirt shall be removed from forms that have been previously used. Concrete Roads and Pavements. 181 Expansion Joints. 20. Width and Location. — Expansion joints not less than 1/4 inch nor more than y^ inch in width shall be placed across the street or road, not more than 25 feet apart. When a curb or combination curb and gutter is used a i/^-inch joint shall be placed between it and the pavement. All expansion joints shall extend through the entire thickness of the pavement. 21. Joint Filler. — The expansion joint filler for open joints shall be a suitable bitumen that will not become soft in hot weather nor hard and brittle in cold weather. Expan- sion joints may also be formed by inserting during construc- tion and leaving in place a total thickness of i/4 inch of tarred paper or tarred felt. 22. Protection of Edges. — When required by the engineer in charge, the concrete at the expansion joints shall be pro- tected with metal. Unless protected by metal or filled wifh tarred paper or felt, the upper edges of the concrete shall be rounded to a radius of % inch- Measuring and IVIixing. 23. Measuring.— The method of measuring the materials for the concrete, including water, shall be one which will insure separate uniform proportions at all times. A sack of Portland cement (94 pounds net) shall be considered 1 cubic foot. 24. Machine Mixing. — When the conditions will permit, a machine mixer of a type which insures the uniform pro- portion of the materials throughout the mass, shall be used. The ingredients of the concrete or mortar shall be mixed to the desired consistency and the mixing shall continue until the cement is uniformly distributed and the mass is uniform in color and homogeneous. 25. Hand Mixing. — When it is necessary to mix by hand the materials shall be mixed dry on a water-tight platform until the mixture is of uniform color, the required amount of water added, and the mixing continued until the mass is of uniform color and homogeneous. 26. Retempering. — Retempering, that is remixing the mortar or concrete that has partially hardened, with ad- ditional water, will not be permitted. TWO-COURSE PAVEMENT. Base. 27. Proportions. — The concrete shall be mixed in the proportion of 1 sack Portland cement, 2^^ cubic feet fine ag- gregate, and 5 cubic feet coarse aggregate. 28- Consistency. — The materials shall be mixed with sufficient water to produce a concrete of a consistency such that mortar will flush to the surface under light tamping, but 182 Concrete Roads and Pavements. which can be handled without causing a separation of the coarse aggregate from the mortar. 29. Placing. — After mixing, the concrete shall be handled rapidly into place and successive batches deposited in a con- tinuous operation, completing sections between expansion joints without the use of intermediate cross forms or bulk heads. Concrete shall not be used that has partially hardened. The concrete shall be well tamped to a surface the thick- ness of the wearing surface below the established grade of the pavement. Workmen shall not walk on freshly laid con- crete, and if sand or dust collects on the base, it shall be re- moved before the wearing course is applied. 30. Reinforcing. — On streets more than 20 feet wide not having car tracks, the pavement shall be reinforced with wire fabric or with plain or deformed bars. The cross sec- tional area of metal shall amount to at least 0.041 square inches per foot measured parallel to the axis of the street, and at least 0.025 square inches per foot measured perpen- dicular to the axis of the street. The reinforcing metal shall be placed upon and slightly pressed into the concrete base immediately after the base is placed. Reinforcing metal shall not cross expansion joints and shall be lapped sufficiently to develop the strength of the metal. Wearing Course. 31. Proportions. — The mortar shall be mixed in the man- ner hereinbefore specified in the proportion of 1 sack Port- land cement and not more than 2 cubic feet of aggregate for wearing course. 32. Consistency- — The mortar shall be of a consistency that will not require tamping, but which can be easily spread into position with a template or straight edge. 33. Thickness. — The wearing course of the pavement in residence districts shall have a minimum thickness of lYz inches, and in business districts a minimum of 2 inches in thickness. 34. Placing. — The wearing course shall be placed im- mediately after mixing, and in no case shall more than 50 minutes elapse between the time the concrete for the base is mixed and the time the wearing course is placed. 35. Finishing.— After the wearing course has been brought to the established grade with a template or straight edge, it shall be worked with a wood float in a manner to thoroughly compact it and produce a comparatively smooth surface, free from depressions or inequalities of any kind. The finished surface of the concrete shall not vary more than % inch from a 2-foot straight edge placed upon the con- crete in any position. 36. Coloring. — If artificial coloring is used, it must be incorporated with the entire wearing course and shall be Concrete Roads and Parenicnts. ISo mixed dry with the cement and aggregate until the mixture is of uniform color. In no case shall the amount of coloring used exceed 5 per cent of the weight of the cement. ONE-COURSE PAVEMENT. The general requirements of the specifications covering two-course work will apply to one-course work with the fol- lowing exceptions: 37. Proportions. — The concrete shall be mixed in the pro- portion of 1 sack Portland cement to not more than 2 cubic feet of fine aggregate (paragraph 2) or aggregate for wear- ing course (paragi-aph 3) and 3 cubic feet of coarse aggre- gate passing a 1-inch ring. 38- Placing and Finishing. — The concrete shall be placed and finished as provided for under "Two-Course Pavement," "Base" and "Wearing Course" respectively. 39. Reinforcing. — When a one-course pavement is rein- forced the metal shall be placed at the middle of the section. The minimum amount of metal shall be as specified under "Two-Course Pavement." Crown. 40. Amount. — All types of concrete pavement shall be given a rise or crown at the center of at least 1-lOOth but not more than 1-75 of the width of the pavement. A portion of this crown may be obtained by increasing the thickness of the pavement at the center rather than by laying a pave- ment of uniform thickness on a crowned sub-grade or sub- base. Protection. 41. Treatment. — As soon as the concrete has hardened sufficiently to prevent being pitted, the surface of the pave- ment shall be sprinkled with clean water and shall be kept wet for at least four days. Concrete pavements on roads shall be covered as soon after finishing as it is possible to do so without damaging the surface, with at least 2 inches of dirt, which shall be kept wet for at least four days. Before covering with dirt, the pavement shall be sprinkled with water as above specified. The pavement shall not be open to traffic until the engineer so directs. 42. Temperature Below 35° Fahr. — If at any time during the progress of the work the temperature is, or in the opinion of the engineer, will, within 24 hours drop to 35 degrees Fahrenheit, the water and aggregates shall be heated and precautions taken to protect the work from freezing for at least 5 days. In no case shall concrete be deposited upon a frozen sub-grade or sub-base. Shoulders. 43. Construction. — On streets where the pavement does not occupy the full width of the street, and on roads, a gravel IS-i Concrete Roads and Pavements, or crushed stone shoulder at least 2 feet wide shall be con- structed on each side of the pavement. The surface of the shoulders shall have a slope away from the pavement of IV2 inches per foot, and a thickness of 2-foot width adjoining the concrete, at least equal to the minimum thickness of the concrete. Wearing Surface of Bitumen and Fine Aggregate. 44. Construction. — Where a wearing surface of bitumen and fine aggregate is used, it shall preferably be placed upon a one-course pavement, constructed as hereinbefore specified, but may be used also on two-course work. 45. Expansion Joints. — Before applying the bitumen to the concrete, all open expansion joints shall be filled as here- inbefore specified. Where required by the engineer in charge, concrete at the expansion joints shall be protected with metal. 46. Bitumen. — The bitumen shall be of a quality speci- fied by the engineer. 47. Placing Wearing Surface. — After the concrete has hardened for at least 7 days the thoroughly cleaned dry sur- face of the pavement shall be covered with hot bitumen applied with a sprinkling wagon designed for the purpose, or with suitable hand sprinkling cans. The hot bitumen shall immediately be evenly distributed over the concrete by brush- ing with suitable brooms, and then covered with the required amount of fine aggregate (paragraph 3). 48. Amount of Bitumen and Fine Aggregate. — Approxi- mately 'V2 gallon of bitumen shall be applied per square yard of pavement and approximately 1 cubic yard of fine aggregate shall be applied per 150 square yards of pavement. Protection. 49. Open to Traffic. — The pavement shall not be open to traffic until the engineer so directs. APPEXDIX B. WAYNE COUNTY SPECIFICATIONS. Parties. For the sake of brevity, the Board of County Road Com- missioners for the County of Wayne will be referred to in these specifications as the Board; the person, firm or corpo- ration to whom the contract shall be awarded will be referred to as the Contractor; and the engineer employed by the Board will be referred to as the Engineer. Plans and Drawings. The plan, profile and cross sections on file in the office of the Board show the general locations, profile, details and dimensions. The work will be constructed in all respects ac- cording to the above mentioned plans, profile and cross sec- tions, which forms a part of these specifications. Any variation of location, profile, size and dimensions from that shown on the plans, which may be required by the exigencies of construction, will in all cases be determined by the Engineer; and the Contractor shall not, on any pretense, save that of the written order of the Board, deviate from the intent of these plans and specifications. On all drawings, figured dimensions are to govern in cases of discrepancies between scale and figures. Commencement of Work. The work embraced in these specifications shall be begun not later than , and carried on regularly and uninterruptedly, unless the Board shall otherwise direct, and with such force as to insure its completion within the time specified in the contract. The Contractor will give the Board ten days' notice before commencement of the work, and also notice that he has on hand or available the necessary material to uninterruptedly carry on the work to completion. After the work shall have been commenced, if the same shall be interrupted and delayed by the Contractor from any cause whatever,' the Board shall have the right to hire an in- spector or watchman and put him in charge of the road dur- ing the interruption, and to deduct the wages paid such em- ploye from amount due the Contractor. Orders to Be Obeyed. Whenever the Contractor is not present on the work orders will be given to the superintendents or overseers who may be in immediate charge thereof, and shall by them be Board or its duly authorized agents, in anything relating to (185) 186 Concrete Roads and Pavements. the work or shall appear to the Board to be incompetent, dis- orderly or unfaithful, he shall, upon the order of the Board, be at once discharged, and not again employed on any part of the work. Tiling. If the work is to be constructed alongside a street railway track, the first work to be done will be the laying of a course of 3-inch land tile on the side of said road next to said track, distant four feet from and parallel with the nearest rail, and at the depth shown on plans. Before the filling back is per- mitted, the tile must be covered their entire length and one- half their circumference with a layer of tar paper, to keep sand and other material from washing through the joints. Each proposal must state the price per lineal foot at which the bidder will undertake to do the tiling as above in- dicated; but the Board reserves the right to reject that part of the proposal relating to tiling, and do that part of the work by day labor, and to accept that part of the proposal relating to roadway proper only, on those parts relating to roadway proper and open ditching; in either of which cases the work of tiling at any given point must be completed be- fore the work on the roadway proper is begun. Open Ditching. If the work to be constructed is not alongside a street rail track, an open ditch must be dug along both sides of said road beyond the earth shoulders, location and dimensions of said ditches being shown on plans. This work may be done either before or after the roadway proper; but if done before the ditches must be kept free and clear from rubbish and refuse during the construction of the roadway proper, and left in as good condition in every way as it would have been if done after the concreting and building of shoulders. If the work to be constructed is alongside a street railway track, then an open ditch will be dug only on the side of the work opposite the street railway track. Each proposal must state the price per lineal foot at which the bidder will undertake to do the open ditching as above indicated; but the Board reserves the right to reject that part of the proposal relating to open ditching and do that part of the work by day labor, and to accept that part of the proposal relating to roadway proper only or those parts relat- ing to roadway proper and tiling. Grading. The Contractor shall do all the excavating and filling necessary to bring the subgrade to the required elevation shown on plans and designated by grade stakes. After the subgrade has been prepared, and before any materials are drawn thereon, it shall be rolled with a steam roller weighing at least ten tons. Wherever soft spots occur in the subgrade Concrete Boads and Pavements. 18Y which cannot be made hard by rolling, the soft material must be removed and material which will pack with rolling must be substituted, and thereafter rolled to the required hardness. Cement. The cement to be used has been contracted for by the Board at per barrel, cloth sacks, delivered in carload lots at any railroad siding in Wayne County, on 30 days' time, subject to discount of Ic per barrel if paid within ten days after the car is placed on the siding to which originally or- dered. Cloth sacks will be charged at 10c each (included in above price) and when returned to the factory of the company furnishing same, freight prepaid, in good condition, subject to factory count and Inspection, will be credited at the same price as charged. The contractor must order and pay for the cement as per contract referred to, and must take care of and return to the factory all sacks, freight prepaid, in order to be entitled to the credit for same. The contract referred to is on file in the office of the Board, and may be seen upon request. Sand and Pebbles. The sand to be used has been contracted for by the Board at prices ranging .... to . . . . , and the pebbles at prices ranging from .... to . . . . , delivered at various sidings in Wayne County. The Contractor must order and pay for the sand and pebbles to be used on the work, and must order both from the same shipper, the shipper to be designated by the Board at the time the Contractor asks to see the specifica- tions. The contracts for the material are on file in the office of the Board and may be seen upon request. Concrete. Concrete shall consist of two parts of cement, three parts of sand, and six parts of pebbles, evenly and thoroughly mixed; parts of cement, sand and pebbles to be determined by measurement. Mixing. All concrete shall be mixed in mechanical batch mixers, which the Contractor shall furnish, of a type to be approved by the Board; and measurements of all material shall betaken in manner to be approved by the Engineer. Placing the Concrete in Position. Before placing the concrete, 2 inch x 7 inch plank shall be placed on edge and staked in line with the outer edge of the pavement, the upper edge of said plank to conform to the finished grade of the road. The workmen shall place the concrete in position in the pavement where directed, and it shall be well tamped. 188 Concrete Roads and Pavements. Finishing the Surface. The Contractor shall employ at least two men whose special duty it shall be to use a strike board having a curva- ture corresponding to the crown of the road, so that the top can be properly stroked off. At night, and at any other time when the work is discon- tinued for a time, all work must be completed up to an ex- pansion joint, hereinafter provided for. In other words, no section of the pavement will be allowed to be left unfinished for a longer period than 20 minutes if work thereon has been started. In the work of placing the concrete in position, and in finishing the subgrade and all other work done under the contract, all foot and other traffic, both of employes and other- wise, must be kept off the top of the concrete until it has thoroughly set; and the Contractor must provide such bridges and other devices as will effectually carry out the provisions of this paragraph. Protection of Concrete After Laying. After the concrete is laid, and until it has thoroughly set, it shall be protected from the sun by a canvas or other suit- able covering, in a manner to be approved by the Engineer. When, in the judgment of the Engineer, the concrete is sufficiently hard to warrant, this covering shall be removed and the concrete covered with a layer of sand or gravel, about 2 inches in depth, or such other device as may be approved by the Engineer, and sprinkled and kept damp 8 days, to prevent the surface of the concrete from drying out too rapidly while setting, which covering shall be left on the concrete for a period of seven days, and then removed and taken away from the road or otherwise disposed of in manner to be approved by the Engineer. Expansion Joints. To allow for expansion the pavement shall be built in sections 25 feet in length, and at each end of each section a soft steel plate 3-16 inches thick, extending the entire width and depth of the road shall be imbedded in the concrete and fastened to the section by projections from the steel or in some other manner satisfactory to the Board. It is hereby expressly stipulated that the joints furnished by the R. D. Baker Company, Home Bank Building, Detroit, will be satis- factory. Between these sections, cutting the entire depth of the concrete, shall be placed an asphalted felt, about Vs of an inch thick. Crossing Over Subgrade. Before any concrete pavement is constructed, and after the subgrade has been prepared, the Contractor shall provide sufficient planks at his own expense and place and maintain Concrete Roads and Pavements. 189 crossings over said subgrade when the same is wet or muddy, unless he shall be excused therefrom, in writing, by the Engi- neer. Crossings for foot pasengers shall be placed at each cross street to accommodate the public. Shoulders. After the pavement is laid, earth shoulders must be built on each side thereof, of sufficient width to bring the total width of the road from berm to berm up to feet, as shown on plans. These shoulders must be built in layers not exceeding 4 inches in depth, and each layer must be well packed before the next layer is placed. When completed, the shoulders must be rolled as directed by the Board, with a roller to be approved by the Board; but such rolling will not be permitted until the concrete has thor- oughly hardened, and in any event not until at least 14 days have elapsed after the laying of the concrete opposite. Engineer's Stakes. The work to be done will be staked out by the Engineer, and any stakes broken or removed through carelessness of the Contractor or his employes will be replaced by the Engi- neer at a cost to the Contractor of one dollar each. The Con- tractor shall give 24 hours' notice when he needs the services of the Engineer. Material on Road. Material delivered on the road in connection with the work must be neatly and compactly piled along the sides in such manner as to cause the least inconvenience to the public and the adjacent property owners. Private drives and road crossings must be kept open as far as practicable, and planked when directed, to the satisfaction of the Engineer. Shade trees and other improvements shall be protected by the Con- tractor from all damage by stone or otherwise. Surplus Earth. All earth not needed for filling or shoulders or otherwise in connection with the work, must be disposed of by the Con- tractor in manner to be approved by the Engineer, at some point not further distant from point of origin than 1,000 feet. Obstructing Travel. Travel upon the road, and upon intersecting roads and alleys, shall not be inconvenienced needlessly; nor shall any portion of the roadway be opened up, nor shall the same be wholly obstructed, except as directed by the Engineer; in which case the Contractor shall cause plain and properly worded signs, "Road Closed, by Order of the Board of County Road Commissioners," announcing such fact, to be placed with proper barricades, and with other signs by day and lanterns by night, plainly indicating the nearest route around 190 Concrete Bonds and Pavements. the obstructed portion, at the nearest cross road beyond each <3nd of such obstructed portion, and upon intersecting roads, so that travel can pass around same in the shortest and easiest way. Liabilities of Contractor. The Contractor must provide a watchman at each end of the road continuously, day and night, and also red lights by night, to effectively keep travel off the pavement, until re- lieved therefrom by the Engineer, in writing; and the former must assume, and will be held liable for, any and all damage which may arise from his neglect to do so, or from any omis- sions on his part. All loss and damage arising from the nature of the work to be done, or from any unforeseen or unusual obstruction or difficulty, which may be encountered in the prosecution of the work undertaken by him, or from the action of the elements,, shall be sustained and borne by the Contractor. Inspection. The work shall at all times be subject to inspection by the Board and its agents; but such inspection shall not re- lieve the Contractor from any obligation to perform said work strictly in accordance with these specifications; and the work not so constructed shall be removed and made good by the Contractor whenever so ordered prior to final acceptance, without reference to any previous oversight in inspection. Defects Before Acceptance. All depressions, defects and imperfections in any portion of the pavement, whether due to public travel, rain, snow, ice, frost, or other causes, before final acceptance of the work by the Board, shall be repaired and made good by the Con- tractor at his own expense. All rubbish which may accumu- late during and by reason of the work herein provided shall be removed by the Contractor as fast as the pavement is laid, and the streets left clean and in good condition. Payments. The Engineer will, on or about the first day of each calendar month during the progress of the work, make and deliver to the Board an estimate, showing, as nearly as he can approximate the same, the number of lineal feet of road- way that have been completed; from which estimate the Board will compute the amount due the Contractor on a pro rata basis; and, after deducting 20 per cent of the whole amount earned, and the sum of all previous payments, will draw its voucher in favor of the Contractor for the balance of the amount found to be due. When the work is completed and accepted, and final estimate is made, the Board will draw its voucher in payment of the balance due the Contractor; provided, that if, in the Concrete Boads and Pavements. 191 judgment of the Board, the proper execution of its work on other roads requires, they may retain an amount equal to the state reward earned on said road until such state reward is paid into the Good Roads Fund of Wayne County. Demurrage, Overshipments, Etc. Inasmuch as all material must be ordered by the Con- tractor, and unloaded and handled by him, he will be expected to order only so much thereof, respectively, as is required for use on the work, and in such quantities as can be conveniently taken care of by him. Any demurrage or storage charges ac- cruing on any material ordered or shipped, and any additional freight or switching charges accruing by reason of his failure to give proper shipping directions as above required, and charges for any overshipment made, must be assumed and adjusted by the Contractor; and the Board reserves the right to hold back a sum sufficient to cover same until they are properly adjusted. And if it shall appear to the Board after a reasonable time, that the Contractor intends to disregard, or may be unable or unlikely to arrive at a speedy adjustment of any or all of such charges, the Board reserves the right to pay them, and deduct the amount so paid from any amount found due the Contractor. Proposals. All proposals must be made upon forms designed by the Board, and must give all the information called for or indi- cated by such forms; and must be on the basis of the Con- tractor furnishing all materials, tools, machinery, appliances and labor, except as herein otherwise expressly provided, necessary for the efficient and proper carrying on of the work. All proposals must be made on the basis of a given price per lineal foot, and must state separately the price for tiling, open ditching, and all other work (which last is designated herein as "roadway proper"). The Board expressly reserves the right to accept the proposal for a greater or less distance than that given in the description of the road above, based upon the amount of money available for use on the road, prob- able cost of inspection, and other considerations. All proposals must be sealed; addressed to Wm. F- Butler. Chairman; endorsed, "Proposal to build Road"; and accompanied by a certified check on some solvent bank, payable to Wayne County, in the sum of Dollars; which check of the successful bidder is to be forfeited as liquidated damages and placed to the credit of the Wayne County Good Roads Fund in case such bidder shall fail to execute a contract to construct the pavement in accordance with these specifications and his proposal, and furnish the bonds herein required, within five days after presentation of draft of same. 192 Concrete Roads and, Pavements. Proposals will be received up to 2 p. m., standard time, of 1912, and not later, and then publicly opened. The right to accept or reject any or all proposals is expressly reserved. Engineer's Estimate. A copy of the Engineer's estimate of the quantities of materials required is attached hereto, marked Exhibit A, The quantities given are the result of calculation, but are to be considered only as approximate. The Contractor is expected to satisfy himself as to the nature, character and quantity of the labor and materials required by a personal examination of the work contemplated. Assignment of Contract or iVIoneys. The Contractor shall not assign nor transfer the contract, nor sublet any portion of the work embraced in it, nor give an order for the payment of any moneys due or to become due by virtue of the contract or of work done under it, with- out the consent of the Board, in writing, being first obtained. Work and Forfeits. If the Contractor shall fail to complete the work wtihin the time specified in the contract, a sum sufficient to pay for inspection and other expenses of the Board, not, however, exceeding in all fifteen dollars per day for each and every day thereafter (Sundays and legal holidays included) shall be de- ducted from the amount due under the contract, as stipulated damages for failure to complete the work within the time specified therein; provided, however, that all days on which work is suspended by order of the Board or Engineer shall be deducted from overtime, if any there be. Bills for Extras. No bills for extras, for labor or material furnished, shall be considered or allowed under any circumstances after the final estimate has been allowed and the pavement duly ac- cepted; nor will any bills for extras, labor or material fur- nished, be considered or allowed unless said extra work or materials furnished shall have been agreed upon in writing, stating price in detail or aggregate, signed by a majority of the Board and the Contractor, before such extra work is done or materials furnished; and upon completion of such extra work, the Contractor shall immediately file with the Board a statement or bill of items, in duplicate, showing the full amount of his claim for work or materials furnished under the agreement; otherwise he shall be deemed to have waived his claim. Bonds of Contractor. The Contractor will be required to execute and furnish, contemporaneously with the execution of the contract, a Concrete Roads and Pavements. 193 surety bond in the sum of Dollars, conditioned on the faithful performance of the contract, to indemnify and save harmless the Board from all suits and actions of any name or description brought against them on account of any act or omission of the Contractor or his agents. Any change made in the plans, specifications, agreements or quantities, whether made with or without the consent of the surety company, shall in no way vitiate said bond; the right of the Board to make such changes as it sees fit being expressly reserved. The Contractor must further agree that so much of the money as may be due him under and by virtue of the contract and work performed thereunder as shall by the Board be deemed prudent, may be retained by them until all suits and claims for damages as aforesaid, shall have been settled, and satisfactory evidence to that effect furnished to the Board. The Contractor shall also furnish bond in the penal sum of Dollars, provided for by sections 10743 and 10744 of the Compiled Laws of 1897, and amendments thereto. The Contractor must also furnish surety bonds in the sum of Dollars, conditions upon the maintenance and proper repair of said road for a period of two years from and after the date of its completion. APPENDIX C. MASON CITY SPECIFICATIONS. 1. All streets prior to laying any pavement thereon, shall be graded so that the pavement will be at the estab- lished grade when completed. After excavating to sub-grade, unless the engineer deem the natural ground a proper foun- dation, excavation shall be continued until solid ground is reached, and then re-filled to sub-grade with sand, gravel or broken stone. 2. The contractor shall be required to remove, at his own expense, all obstructions, such as trees, old blocks, debris, etc. 3. All excavated material, gutter stones, planks, mac- adam, crossing stones, old curbs, surplus earth, etc., shall be the property of the city and be deposited by the contractor in such place and manner as shall be directed by the engineer, the distance not to exceed 3,000 feet. No plowing will be allowed within 3 inches of the bottom of the foundation. 4. When the street shall have been graded and shaped to its proper form, it shall be thoroughly rolled with a ten- ton roller to a thoroughly compact surface. If the ground is wet, sand or gravel is to be put on before rolling. 5. Any depression descovered after this rolling, shall be filled to sub-grade, and this repeated until a road-bed per- fect as to grade and form shall have been made. 6. When the use of the roller is impracticable, the foun- dation must be thoroughly puddled and rammed until com- pacted to the satisfaction of the engineer. 7. Upon the roadway thus formed, will be laid a founda- tion of Portland cement concrete five (5) inches thick, to be made as follows: One part by measure of Portland cement: 2 parts by measure of clean, sharp sand, and 5 parts by meas- ure of broken stone. 8. The sand and cement shall be thoroughly mixed into mortar, at the proper consistency, with a batch mixer ap- proved by the engineer. Broken stone, thoroughly cleaned of dirt, drenched with water, but containing no loose water in the heap, shall then be added to the mortar in the proper proportion. The concrete will then be turned and mixed until each fragment is thoroughly coated with mortar. 9. A strictly wet mixture will be required. 10- The concrete thus prepared shall be placed immedi- ately in the work. It shall be spread and thoroughly com- pacted until free mortar appears on the surface, which shall Concrete Roads and Pavements. 195 be made smooth and parallel to the surface of the finished pavement. The whole operation of mixing and laying each batch of concrete shall be performed in an expeditious and workmanlike manner and be entirely completed before the cement has begun to set. 11. No re-tempering of concrete will be permitted, and concrete in which the mortar has begun to set will be re- jected. 12. The thickness of this concrete to be five inches after the same has been compacted. 13. Extreme care should be taken that the sub-grade is kept moist while this concrete is being put in place. 14. No concrete shall be laid when the temperature at any time during the day or night falls below 35° above zero, Fahrenheit. 15. Upon the concrete heretofore specified shall be im- mediately laid a wearing surface 2 inches in thickness to be made as follows: One part by measure of Portland cement, 2 parts by measure of coarse, clean, sharp sand. The sand and cement shall be thoroughly mixed into mortar of the proper consistency with an approved batch mixer. 16. The mortar thus mixed will be immediately laid upon the concrete heretofore specified. 17. Before this mortar has begun to set, it will be fin- ished off to a smooth surface with a wood float, and before it has completely hardened, it shall be roughened by brush- ing with a stiff vegetable brush or broom. 18. All forms for expansion and contraction joints shall be made of iron or steel in the form of a template, cut to the desired shape of the street, according to the plans, and of sufficient strength to resist springing out of shape. All mortar and dirt shall be removed from the forms that have been previously used. The forms shall be well staked to the established lines and grades. 19. Contraction joints shall be made entirely through the pavement every 12 1^ feet at right angles with the street except at expansion joints. The edges of all unprotected expansion joints and all contraction joints shall be rounded to a radius of ^2 inch, with proper tools. 20. The sides of all expansion joints that are at right angles with the curb lines, shall be protected by a protec- tion plate to be of soft steel one-quarter (i/4) of an inch in thickness, 2^^ inches in width, a shear member to be punched from the side of the plate, and bent at right angles to the same. Shear member to be 6 inches long and % of an inch In width, spaced 10 inches center to center. Protection plates- shall be in sections not less than feet in length, and cut to the desired crown of the street. 196 Concrete Boads and Pavements. 21. The curvature and cross-sections of the pavement to be made according to the plans governing the same. 22. The cement used in the work will be submitted to the tests approved and recommended by the American So- ciety of Civil Engineers, which it must stand to the satisfac- tion of the engineer. 23. All Portland cement used in the work shall be Mason City Portland cement, or other Portland cement equally as good, which shall be protected from the weather, free from exposure to air slacking and from moisture, until used. 24- The sand shall be clean, sharp sand. 25. The stone used for the concrete shall be of the best quality of hard limestone, or other stone equally as good, and shall be broken to such a size that the fragments shall not be larger than will pass through a li/^-inch ring and not smaller than a hazel nut. It shall be free from dust, dirt, loam or other objectionable material and shall be screened when necessary over a i/^-inch screen to eliminate dust and small particles. 26. An expansion joint 1 inch in width shall be left next to the curb on each side of the street or alley, also an ex- pansion joint ^ inch in width will be left every 37 1/^ feet across said pavement at right angles to the curbs. Said ex- pansion joints are to be filled with an asphalt paving filler of proper quality and consistency approved by the engineer. It will be applied while heated to a temperature of about 400° Fahrenheit, and shall be so applied that said expansion joints shall be thoroughly filled clear to the top of surface of said pavement. 27. Care shall be taken to obtain a surface free of ridges, at expansion joints, and depressions or unevenness in the surface, that will detract from its appearance, or cause water to lay on the pavement. 28. Any sections having such inferior surface will be re- jected, and shall be rebuilt by contractor at his own expense. 29. Care shall be taken to make the expansion joints in such a manner that they are practically the same width throughout their depth. 30. Extreme care must be exercised in removing tem- plates or divisions used to make expansion joints; the break- ing out of any portion of the pavement, in removing such templates and forms, will not be tolerated, and such dam- aged portions of the work shall be torn out and replaced in good condition by the contractor at his own expense. 31. The contractor shall keep pavement sprinkled con- stantly and kept wet once a day for one week after it is laid or longer if deemed necessary by the engineer. 32. The contractor shall keep the street closed to traffic at least two weeks after the completion of same. APPEXDIX 1). THE SPECIFICATIONS OF THE ILLINOIS HIGHWAY COMMISSION FOR CONCRETE ROAD CONSTRUCTION. Concrete Materials. Cement. — Some standard brand of Portland cement shall be used which has been in practical use on public works and shall have proved satisfactory therein. No brand of cement shall be used which the engineer deems unfit for the work, nor shall any cement be used which fails to give satisfactory results according to the standard methods of testing as pro- vided by the American Society for Testing Materials. The contractor shall provide sufficient means to protect the cement against dampness, and no cement shall be used which has become caked. The contractor shall notify the engineer in writing what brand or brands he intends to use, and before ordering the cement shall receive the written approval of the engineer as to the brand selected. It is understood that such approval merely covers the selection of the brand; that the cement itself may be rejected if it fails to meet the requirements herein specified. Coarse Aggregate. — The coarse aggregate shall consist of clean, hard, sound flint or other hard siliceous pebbles, having a reasonably uniform gradation from a size which will pass through a 1-inch screen to a size that is retained on a %-inch screen, and no gravel composed in part of slate, shale, disintegrated limestone, or other equally soft stone, can be used. Crushed granite or trap rock, graded to the size pro- vided above, may be used. Crushed limestone, graded to the size specified above, may be used only upon the approval of the engineer. Fine Aggregate. — The fine aggregate shall consist of clean, sharp quartz grains, and shall not contain over 2 per cent of clay or loam. The fine aggregate shall be reasonably uniformly graded from a size which will pass through a %- inch screen down. Sand containing disintegrated shale, slate or limestone shall not be used. Grading oT Aggregate. The specification that the coarse and fine aggregates must be reasonably well graded shall be interpreted to mean that the percentages of the aggregates passing screens of (197) 198 Concrete Roads and Pavements. various sizes shall be within the limits given in the follow- ing tables: Table of Gradation of Coarse Aggregate. Allowable limits of Size of screen. Percentage passing through. 1-inch square mesh 100 ^-inch square mesh Not less than 45 nor more than 60 Table of Gradation of Fine Aggregate. Size of screen. Allowable limits of Percentage passing through. %-inch square mesh 100 ife-inch square mesh Not less than 65 nor more than 85 If the contractor desires to use aggregate which is not graded in accordance with the table, he must submit a sam- ple of 50 pounds of such material to the Illinois Highway- Commission, Springfield, 111., one week prior to the date of letting of this contract. His sample of aggregate will be analyzed and, if found suitable, its use will be approved in writing and the amount of cement that must be used with such aggregate will be stated. The aggregate used in the construction work must then be graded in accordance with the sample submitted, and must be of the same kind and quality as the sample, and the amount of cement used must be the quantity required by the engineer in accordance with this paragraph instead of the amount provided in paragraph 32. [Proportions for concrete.] Use of Gravel. The use of gravel made up of a mixture of the coarse and fine aggregates described above will not be permitted. If the contractor wishes to use such material, he must screen it to the sizes specified above before proportioning the aggregate for mixing. Concrete Mixer. The concrete mixer used on the work provided for herein shall be a batch mixer of a type approved by the engineer. The concrete shall receive at least four complete turns of the drum before being discharged, and if, in the opinion of the inspector, a greater amount of mixing is required, this number of turns shall be increased until a thoroughly mixed concrete is secured. Proportions for Concrete. The concrete for the work provided for herein shall con- sist of 1 part of cement, 2 parts of fine aggregate, and 3^^ parts of coarse aggregate. The aggregate shall be placed in the mixer in such manner as to insure that a uniform amount of each class of aggregate is used in each batch of concrete; and the method of measuring the aggregate, whether in wheel- Cono'cie Roads and Paconents. 199 barrows, or otherwise, shall be approved by the inspector, 1 sack of cement to be considered as 0.95 cubic feet, and all measurements to be by volume. Water. The water used in mixing the concrete shall be clean. Size and Kind of Roller. Wherever it is provided herein that rolling shall be done on the roadbed or macadam shoulders, a three-wheel self- propelling roller, weighing not less than ten nor more than twelve tons shall be used. Roadbed. The roadbed will be considered as that portion of the road upon which the concrete roadway and macadam shoulder are placed. The roadbed shall consist of the natural earth which has been brought to the proper elevation and cross section and rolled until firm and hard. If sandy or other soil is encountered which will not compact readily under the roller, a small amount of clay or loam shall be added so as to secure a firm, hard surface after rolling. The roadbed shall be thoroughly saturated with water immediately before concrete is placed. Shoulders and Side Roads. After the completion of the concrete roadway and ma- cadam shoulders, the side roads are to be shaped in accord- ance with the cross section shown on the plans and shall be rolled, care being taken not to allow the roller on the edge of the concrete roadway. Upon completion, the cross slope of the concrete roadway, macadam shoulders, earth side roads and ditches shall be as shown on the plans. Thickness of Concrete Roadway. The concrete roadway shall have, after completion, the thickness shown on the plans. If a greater thickess is laid than that shown on the plans, no extra compensation will be made therefor. Under Drains. An under drain 8 inches wide and 6 inches deep shall be constructed under each of the concrete roadway edges, the entire width of the drain being under the pavement. This under drain shall be filled with broken stone or coarse ag- gregate before the concrete is placed. At the end of each expansion joint or at intervals of not to exceed 50 feet, blind cross drains, not less than 8 inches wide, shall be con- structed from the longitudinal drains before mentioned, to the gutter. These cross drains shall be of such a depth as to drain readily from the longitudinal drains to the gutter, and shall be filled with at least 6 inches of crushed stone or coarse aggregate, and then covered with earth, except that 200 Concrete Roads and Pavements. such part of the cross drain as lies under the macadam shoulder shall be filled with stone when the shoulder is con- structed. The longitudinal and cross drains shall be com- pleted before the concrete roadway is constructed. Side Forms. The concrete roadway shall be placed between side forms of 2-inch plank. The side form plank shall be of a width equal to the thickness of the pavement at the edge. The side form planking shall be accurately set to the alignment and grade of the pavement, and shall be held securely in place by adequate stakes and bracing. Intermediate longi- tudinal form boards will not be permitted between the side forms to support the templet. Placing Concrete Roadway. The concrete for the roadway shall be placed between the plank forms before described, the entire thickness of the con- crete being placed at one time. After the concrete has been deposited between the forms, it shall be raked and tamped until the mortar flushes to the top, and the concrete shall be placed in such quantity that there will be a slight excess between the forms. The surface of the roadway shall then be shaped to conform to that which is shown on the plans by striking off with a templet cut to the proper shape. This templet shall be drawn along the forms, and shall be held securely against the top of the forms, and shall be moved with a combined longitudinal and crosswise motion which will prevent dragging the larger particles of the aggregate and marring the surface. Finisliing Surface of Concrete Roadway. After the surface of the concrete roadway has been struck off to the proper cross section, it shall be finished with wood fioats. The wood floats shall be used only to flush mor- tar to the porous places in the surface, and great care must be taken not to rub hollow places in the surface. The wood float finish shall be made as soon after the concrete has been deposited as possible, and in no case shall the finishing be delayed until the concrete has taken a set. Covering Concrete Roadway. After the concrete roadway has been finished as above described, the roadway shall be covered with suitable canvas as soon as this can be done without marring the surface, which shall be kept wet, and as soon as the concrete sets sufficiently, the canvas shall be removed and the concrete covered with earth. The earth covering shall be put on at least 1 inch thick and shall be kept constantly wet for two weeks. The roadway shall be kept close to traffic for two weeks, or, if in the opinion of the engineer, the weather con- Concrete Roads and Pavements. 201 ditions make it advisable, the roadway shall be kept closed to traffic a longer period of time. Expansion Joints. Expansion joints shall be provided and spaced as shown on the plans. The expansion joints shall be set at an angle of 60 degrees with the center line of the roadway and shall be of the type shown on the plans. The expansion joints shall be constructed in such manner as to Insure that the metal plates, creosoted blocks, or other device provided for the joints, shall conform to the cross section provided for the roadway; and great care must be exercised in placing these joints to insure that there will be neither a depression nor a raised place at the joint. Cleaning Finished Pavement. When the concrete roadway has been completed for a sufficient length of time to permit a proper setting of the concrete, it shall be cleaned and then opened to traffic. Beveling Edges. If the plans shall provide that the edge of the concrete shall be beveled, then the plank forms shall be removed from the edge of the roadway before the concrete takes its final set, and the edge of the pavement shall be cut off by means of a shovel or other suitable tool so as to give the shape shown on the plans. Macadam Shoulders. The macadam shoulders when completed shall be of the width and thickness shown on the plans. The stone for the macadam shoulders shall be deposited, spread and rolled at least twice over, and then covered with screenings or gravel, sprinkled and rolled. When completed the macadam shoulder shall be true to shape and shall be ^2 inch above the concrete where it joins the concrete roadway. Trimming Sides of Road. The slopes on cuts and fills shall be neatly trimmed to the slopes shown on the plans, and all detritus and surplus materials left after completion of the work shall be removed from the road. APPEIS^DIX E. SPECIFICATIONS FOR BLOME GRANITOID PAVEMENT. Preparation of Sub-Grade. The sub-grade shall conform exactly to the lines and ele- vations shown on the plans or profiles or as furnished to the contractor by the engineer in charge or under the direction of the engineer. The street shall be graded (excavated or" filled as the case may be) to sub-grade, as specified and pro- vided for in the general specifications, in such a manner as to provide a solid foundation for the pavement and all slopes, contours and other shaping required in the pavement shall be formed and provided for in said sub-grade, so that the foundation and pavement hereinafter specified shall be of uniformly the same thickness throughout. The contractor will bid with the understanding that the sub-grade is to be prepared in such a manner as to support the pavement permanently and retain the original grades. Any spongy material, vegetable matter or any material un- suitable as a foundation shall be removed and the spaces re- filled with proper material, tamped or rolled until compact. This clause shall not be waived on account of openings made in the street by any corporation or individual prior to the laying of the pavement. Materials. The cement used for this work to be a standard brand of Portland cement complying with all the requirements of the American Society for Testing Materials. All cement to be delivered on the work in approved packages bearing name, brand or stamp of the manufacturer, and 94 pounds net of cement shall be considered as 1 cubic foot. All cement to be carefully protected from the weather until used. The sand shall be free from clay, loam, vegetable matter and dust. The grains shall vary in size from %-inch down to the finest and so graded that the voids, as determined by saturation shall not exceed 33 per cent of the volume. No wind drifted sand to be used. The stone used in making the concrete shall be of the best quality of limestone, trap rock or other hard stone, or of gravel of size so as to measure not more than 2i/^ inches, and in the event of stone being used same shall not measure under ^4 inch in dimension. Clean, acceptable, pit-run gravel, from which all organic matter and dust has been eliminated, may be used for the (202) Concrete Roads and Pavements. 203 concrete bed or lower course of the pavement. The sizes of sand grains and stone in pit gravel and the proportions of fine and coarse aggregate shall correspond to specifications for sand and stone, and deficiencies shall be made up by the addition of sand or crushed stone or gravel. When delivered on the street these materials shall be placed in such a manner as to be kept clean until used. Mixing and Laying of Concrete, and Formation of the Blome Company Granitoid Blocking. The concrete bed or foundation and the surfacing here- inafter specified shall be constructed and manipulated in ac- cordance with the Blome Company patents and processes, utilizing materials mixed in the proportions and laid as here- inbefore specified. Upon the sub-grade and foundation prepared as herein- before specified the Granitoid Concrete Pavement shall be laid, consisting of 6% inches of concrete at the center of street and gradually decreased to 4i^ inches at the curbs or outer sides of pavement, and on same shall be placed the Granitoid surface blocking of uniform thickness of ly^ inches. Whenever there are street car tracks on the street pro- posed to be paved, the thickness of the concrete bed shall be equal to the average thickness of the concrete above specified uniformly at all points of the areas to be paved. The concrete shall be composed of 1 part of Portland cement, 3 parts of sand and 4 parts of limestone, trap rock or other hard stone or clean gravel. These materials to com- ply with the requirements hereinbefore set forth and shall be mixed by an approved mixing machine, suitable for the purpose, approved by the engineer in charge, each batch being turned at least 5 times before being removed from the mixer. The concrete shall be thoroughly tamped into place and shall be of the thickness specified, after having been com- pacted and shall be carefully rammed into sections separated by expansion joints, all as per the Blome Company patents, and the said concrete shall follow the slopes of the finished pavement so that the surface blocking is, and shall be, of uniform thickness at all points. Granitoid Blocking. After the concrete has been placed and before it has begun to set, there shall be immediately deposited thereon the Granitoid Blocking, which shall be l^/^ inches in thickness, to be composed of 2 parts of approved Portland cement and 3 parts of crushed granite, trap rock, gravel, hard stone or other similarly hard material, which shall be screened with the dust removed therefrom, utilizing the following propor- tions of this material: Substantially 50 per cent to be what is known as %-inch 204 Concrete Roads and Pavements. size, 25 per cent of i/4-mch size, and 25 percent of %-inch size, with all finer particles removed. This material shall be thoroughly mixed with approved cement and after being wetted to the proper consistency and deposited on the con- crete, shall be worked into brick shapes of approximately 4^/^ inches by 9 inches, with rectangular surface similar to pav- ing blocks, all as per special method and utilizing the groov- ing apparatus as employed under the Blome Company patents. The pavement shall be sloped in the manner required by the engineer in charge and in event any part or parts of the pavement, when completed, where slopes, contours, etc., have not been carried out in a true manner, then, under these specifications, the contractor will be required to take up such part or parts, and replace same to the proper level, without expense. Expansion Joints. The contractor shall provide for and form expansion joints across the pavement at such intervals as may be nec- essary, and, where advisable, also along the sides at the curbs or gutters, which expansion joints shall extend entirely through the surface blocking and the concrete and shall be filled with a composition especially prepared for the purpose in accordance with the Blome Company patents. These ex- pansion joints shall be constructed in an extremely careful manner, under specific direction of the engineer in charge. Patents, Trademarks, Etc. All fees for any patent inventions, materials, articles or arrangement or other apparatus that may be used upon or be in any way connected with the construction, erection or main- tenance of the work or any part thereof embraced in the con- tract or the specifications, shall be included in the prices stipu- lated in the contract for said work and the contractor must show conclusively that he has a license permitting and giving him the right to use the patented inventions, materials, articles or arrangement or other apparatus necessary for the construc- tion of the pavement under these specifications and the price stipulated in the contract for said work must include such cost and the contractor must protect and hold harmless the city against any and all demands for such fees or claims. Blome Company trademark plates will be provided show- ing the dates of pavement patents, etc., together with trade- marks, which plates shall be set by the contractor at such locations as may be designated by the Blome Company. APPE^S^DIX F. SPECIFICATIONS FOR BLOME GRANOCRETE PAVEMENT Preparation of Sub-Grade. The sub-grade shall conform exactly to the lines and elevations shown on the plans or profiles or as furnished to the contractor by the engineer in charge or under the direc- tion of the engineer. The street shall be graded (excavated or filled as the case may be) to sub-grade, as specified and provided for in the general specifications, in such a manner as to provide a solid foundation for the pavement and all slopes, contours and other shaping required in the pavement shall be formed and provided for in said sub-grade, so that the foundation and pavement hereinafter specified shall be of uniformly the same thickness throughout. The contractor will bid with the understanding that the sub-grade is to be prepared in such a manner as to support the pavement permanently and retain the original grades. Any spongy material, vegetable matter or any material un- suitable as a foundation shall be removed and the spaces refilled with proper material, tamped or rolled until compact. This clause shall not be waived on account of openings made in the street by any corporation or individual prior to the laying of the pavement. Materials. The cement used for this work to be a standard brand of Portland cement complying with all the requirements of the American Society for Testing Materials. All cement to be delivered on the work in approved packages bearing name, brand or stamp of the manufacturer, and 94 pounds net of cement shall be considered as 1 cubic foot. All cement to be carefully protected from the weather until used. The sand shall be free from clay, loam, vegetable matter and dust. The grains shall vary in size from Vk . inch down to the finest, and so graded that the voids, as determined by saturation shall not exceed 33 per cent of the volume. No wind drifted sand to be used. The crushed stone or gravel used in making the con- crete, shall be of good quality of limestone, trap rock or other hard stone, or of gravel of size so as to measure no more than 2y2 inches, and then graded to the sizes hereinafter mentioned. Clean, acceptable, pit-run gravel, from which all organic (205) 206 Concrete Roads and Pavements. matter and dust have been eliminated, may be used for the foundation course of the concrete. The sizes of sand grains and stone in pit gravel and the proportions of fine and coarse aggregate shall correspond to specifications for sand and stone, and deficiencies shall be made up by the addition of sand or crushed stone or gravel. When delivered on the street, these materials shall be placed in such a manner as to be kept clean until used. Manner of Construction of Granocrete. The Granocrete Pavement shall be 7 inches in thickness at the center of street or roadways, and decreased gradually to 5 inches in thickness at the curbs or outer sides of the pavement after having been made compact. Upon the sub-grade, prepared as hereinbefore specified shall be deposited concrete composed of 1 part of Portland cement and 8 parts of an aggregate consisting of approxi- mately 50 per cent of broken stone or gravel with particles below 1/^ inch eliminated, 15 per cent of i^-inch stone or gravel with the dust removed, and 35 per cent of clean, tor- pedo sand. This selection of sizes of ingredients is made in order to produce a mass which will have sufficient voids or un- occupied spaces to receive enough of the material consti- tuting the top wearing surface or layer, hereinafter described, to secure a firm union between the two, whereby the top surface is effectively anchored to this foundation. These materials shall be mixed by an approved mixing machine suitable for the purpose, approved by the engineer in charge, each batch being turned at least 5 times before being removed from the mixer. The concrete shall be thoroughly tamped into place and to be of the thickness above specified after being compacted, carefully rammed into sections, separated by expansion joints, all as per Blome Company patents and the said concrete shall follow the slopes of the finished pavement so that the surfac- ing is and shall be of uniform thickness at all points. Surfacing. After the concrete has been placed, and before it has begun to set, there shall be immediately deposited thereon the surfacing which shall consist of 1 part of Portland cement, 1 part of coarse, sharp sand, and 1 part of a mass composed of hard broken stone, conglomerate or gravel of sizes herein- after mentioned. The composition of the stone or gravel in the surfacing shall be substantially as follows: Twenty-five per cent of the stone or gravel in the surfac- ing shall be i/4-inch size; 50 per cent shall be of %-inch size, and 25 per cent shall be of i/^-inch size, having in all instances the finer particles eliminated. Concrete Bonds and Pavements. 20' The surfacing matevial shall be thoroughly mixed with approved cement and, after having been wetted to the proper consistency, shall be deposited on the concrete and floated in a manner so as to thoroughly compact all of the in- gredients. The surfacing shall be 1 inch in thickness after having been compacted. The top stratum when compacted, enters the voids of the concrete sufficiently to obtain a firm anchorage thereto, and it is to be understood that definite quantities of material hereinbefore mentioned are employed in the surfacing to protect the sand particles or grain from the effects of travel. The pavement shall be sloped in the manner as required by the engineer in charge, and in the event there should be any part of the pavement, when completed, where slopes, contours, etc., have not been carried out in a true manner, then under these specifications, the contractor will be re- quired to take up such part or parts and replace same to the proper level without expense. Expansion Joints. The contractor shall provide for and form expansion joints across the pavement at such intervals as may be nec- essary, and, where advisable, also along the sides at the curbs or gutters, which expansion joints shall extend entirely through the surfacing and concrete, and shall be filled with a composition especially prepared for the purpose in accord- ance with the Blome Company patents. These expansion joints shall be constructed in an extremely careful manner, under specific direction of the engineer in charge. Patents, Trademarks, Etc. All fees for any patent inventions, materials, articles or arrangement or other apparatus that may be used upon or be in any way connected with the construction, erection or maintenance of the work or any part thereof embraced in the contract or the specifications, shall be included in the prices stipulated in the contract for said work and the contractor must show conclusively that he has a license permitting and giving him the right to use the patented inventions, materials, articles or arrangement or other apparatus necessary for the construction of the pavement under these specifications and the price stipulated in the contract for said work must in- clude such cost and the contractor must protect and hold harmless the city against any and all demands for such fees or claims. Blome Company trademark plates will be provided show- ing the dates of pavement patents, etc., together with trade- marks, which plates shall be set by the contractor at such locations as may be designated by the Blome Company. APPENDIX G. SPECIFICATIONS FOR BITUSTONE PAVEMENT. Excavation. Excavation shall be paid for at the price bid per cubic yard. The portion of the roadway to be improved shall be excavated or filled to the necessary depth below the estab- lished grade of the finished roadway to provide for the thick- ness of 5 inches Bitustone pavement. The sub-grade shall be rolled with a steam roller until its surface is solid, and approximately parallel to the proposed surface of the finished roadway. All excavated material shall be disposed of by the contractor. Bottom Course of Pavement. The bottom course of the pavement shall be laid 4 inches thick upon the previously rolled sub-grade and shall be com- posed of a Portland cement concrete mixed in the proportions of 1 part cement, 3 parts sand or crusher screenings, and 6 parts crushed stone or gravel, slag, broken brick, oyster shells or other mineral aggregate suitable for making concrete. The material used in this concrete shall be of a quality usual in such construction. Bonding Course. Upon the bottom course of the pavement, and while the same is still in a wet and plastic condition, shall be spread and leveled, either by tamping or rolling with a light roller, 1 inch of the Porous Bonding Course composed of hard, dur- able aggregate of approximately uniform size, passing screen openings 1 inch in diameter, and remaining on screen open- ings Vz inch in diameter, mixed with Portland cement in the proportions of 6 parts of the stone and 1 part of Portland cement. This mixture shall not be sufficiently wet to wash the cement to the bottom of the stone, and must be of such consistency as to insure the coating of each individual stone with a thin coating of pure Portland cement, which shall be stiff enough so as not to be displaced in the subsequent manipulation of grading and tamping. The Bonding Course when finished shall produce a surface in which the coated stones are firmly held together at their points of contact. The Bonding Course shall be kept free from dirt and other extraneous matter, and shall be firmly embedded in the con- crete bottom course. (20,S) Concrete Roads and Pavements. 209 Filler. After the Bonding Course has become dry, there shall be poured upon it and into it sufficient Double Bond Asphaltic Filler to penetrate into the voids in the bonding course and leave a slight excess on the surface, enough excess to fill the superficial voids between the projecting stones, and provide a continuous coating of the Double Bond Filler on the surface. Surface Finish. While the filler is still hot and plastic there shall be scattered over it a thin layer of crusher screenings which will pass one-fourth (14) inch screen openings. APPEIS^DIX H. DETAIL SPECIFICATIONS FOR DOLARWAY PAVEMENT. 1. All streets, prior to laying the pavement thereon, shall be graded as directed by the engineer. After excavating the sub-grade, unless the engineer deems the natural ground a proper foundation, excavation shall be continued until solid ground is reached and then refilled to sub-grade with sand, cinders, gravel or broken stone. 2. When the sub-grade shall have been formed and prop- erly shaped, it shall be rolled with a roller weighing not less than ten tons, to a thoroughly compact surface. If the rolling develops wet or soft spots, they must be filled with dry cinders, sand or gravel. 3. Any depression discovered after rolling shall be filled to sub-grade, re-rolled, and this operation repeated until a roadbed perfect as to grade and form shall have been made. 4. When the use of a roller is impracticable, the founda- tion must be thoroughly puddled and rammed until com- pacted to the satisfaction of the engineer. 5. Upon the sub-grade thus formed shall be placed a layer of Portland cement , concrete .... inches thick, of the following proportions: parts by volume of Portland cement; parts of clean sharp sand and parts of broken stone or clean gravel. Within twenty (20) minutes after the concrete is laid it shall be struck off with a template approved by the engineer, and as soon thereafter as practicable shall be fioated suf- ficiently to bring the finer particles to the top so as to pro- duce a smooth, uniform surface. The concrete shall be kept wet, if directed by the engi- neer, for a period of seven days. 6. If gravel is used for concrete, it must be free from clay or other injurious material and shall contain no stone over two inches in diameter. Care must be taken, if the gravel is not screened, that the ratio of the sand to the stone in its composition shall not ex- ceed the above specifications for proportion of materials. 7. If broken stone is used for concrete, it shall be of the best quality of limestone, or other stone equally good, and shall be broken to such size that no fragment shall be larger than will pass through a 2-inch ring, nor smaller than i/^ inch in its greatest dimension. It shall be clean and free from all foreign matter and shall be uniformly graded. 8. The cement used in the work will be submitted to the tests approved and recommended by the American Society for Testing Materials, and any cement failing to comply with (210) Concrete Roads and Pavements. 211 these requirements shall be rejected. All cement to be used on the work shall be suitably protected from exposure to moisture until used. 9. The ingredients of the concrete shall be thoroughly mixed in a mixer approved by the engineer; enough water being added to produce a plastic mass that will flush slightly under light tamping, but not so thin that the mortar will separate from the coarse aggregate. 10. No retempering of concrete will be permitted, and that in which mortar has begun to set shall be rejected. 11. No concrete shall be laid when the temperature at any time during the day or night falls below thirty-five (35°) degrees above zero, Fahrenheit. Longitudinal expansion joints i/^ inch wide shall be con- structed the full length of the pavement, on each side of the street next to the curb. The joints shall extend the entire depth of the pavement and be filled with Dolarway bitumen and coarse sand or grit. Care shall be taken to fill these joints fiush with the surface of the pavement, and before the wearing surface is applied. Transverse expansion joints may be omitted, unless other- wise directed by the engineer in charge of the work. 13. Not less than 10 days after the concrete has been laid as above specified, and is thoroughly set and perfectly dry, the surface shall be brushed vigorously with a wire broom to remove all loose or insecure particles, and immediately before applying the bitumen it shall be swept with house brooms or fiushed with water until clean. After it is perfectly clean and dry there shall be spread over the entire surface a layer of Dolarway bitumen, using not less than one-third nor more than one-half of a gallon to the square yard, said bitumen to be applied at a temperature of not less than 200 degrees Fahrenheit nor more than 250 degrees Fahrenheit. Immediately following the spreading of the bitumen there shall be spread over the entire surface a uniform layer of dry, clean, sharp sand, or fine washed gravel, or screenings, using not less than one (1) cubic yard to one hundred (100) square yards of surface. No bitumen shall be applied when the tem- perature is below 40 degrees Fahrenheit, and the sand or screenings shall be applied while the bitumen is sufficiently soft to permit of their becoming thoroughly imbedded in it. After the sand or screenings have been spread, the street shall be closed to travel for a period of not less than two (2) hours, after which time the street may be opened to travel. Note. — The thickness of the concrete foundation is not specified in the above, nor are the proportions of the materials composing it, as local conditions and requirements must de- termine these points in each individual instance. The Dolar- way Company, however, recommends that the concrete base be composed of a mixture not leaner than 1:2:4 and that its thickness be not less than 5 inches. APPE^^DIX I. SPECIFICATIONS FOR LAYING HASSAMITE. 1. The sub-grade shall be of the same cross section as the finished surface, but of less elevation to the extent of the proposed pavement. 2. In places where fill is required, it may be made with any suitable material excavated from the improvement. All filling must be made in uniform layers not over 6 inches in depth and each layer shall be thoroughly rolled or tamped as may be required to insure a solid bed. No material shall be placed in a filled embankment ex- cept that which is suitable, whether taken from excavation in the road or elsewhere. 3. The roadbed shall be brought to a solid sub-grade of exact cross section, by rolling or tamping as may be required, and any material which does not produce a firm foundation shall not be permitted in foundation. Any such shall be re- moved and replaced by material approved by the engineer. Any extra work to be paid for at cost, plus 10 per cent. Requirements of Materials. 4. All cement used on this work must fulfill the follow- ing requirements. [Standard Specifications of American So- ciety for Testing Materials.] 5. Sand. — The sand for the foundation shall be clean, sharp, and free from clay, loam or organic matter. The sand for the wearing surface shall be of such quality as the con- tractor may determine. 6. The foundation may be of stone, slag or screened gravel. 7. All water necessary for the construction of the pave- ment shall be furnished free of cost to the contractor by the city. Hassam Concrete Foundation. 8. Upon the sub-grade prepared in accordance with the specifications for grading, broken stone shall be spread so that after rolling or compressing, it shall have a uniform thickness of inches. 9. After the stone has been thoroughly compacted and firmly embedded and the voids reduced to a minimum, it shall be grouted with a grout of Portland cement and sand, con- sisting of two parts sand and one or more parts Portland cement, said grout to be mixed in a Hassam Grout Mixer to insure the accurate blending of the ingredients. (212) Concrete Roads and Pavements. 213 This grout shall be poured upon the foundation until all the voids are filled and the grout flushes to the surface — the stone to be lightly rolled or compressed during the process of grouting, leaving uniform surface. 10. No concrete shall be laid when the temperature at any time day or night falls below 26 degrees F. Wearing Surface. 11. The surface of the concrete so produced shall be covered with two layers of bituminous composition, known as Hassamite, in one or more substantially equal coats of ^A gallon each per square yard. This composition shall be ap- plied, when heated, to a temperature of not less than degrees F. and not more than 300 degrees F. Immediately after being applied the first course of composition is to be drifted with screened pea stone, suitable sand or gravel, and rolled with a light steam roller; the second course to be drifted with pea stone, suitable sand or gravel, thoroughly rolled, sufficient sand being added to absorb any surplus com- position. APPENDIX J. TYPICAL SPECIFICATIONS FOR REINFORCED CON- CRETE BRIDGE AND CULVERT CONSTRUCTION.* Plans and Drawings. All concrete masonry shall be built to conform with the lines and dimensions shown on the plans and drawings fur- nished or approved by the engineer in charge, and which are hereby made a part of these specifications- In cases of discrepancies between figured dimensions and scale, the fig- ured dimensions are to govern. Concrete. The concrete shall be of the character and mixed in the proportion indicated on the plans, or as may be indicated in writing by the engineer in charge, or as hereinafter specified. All concrete shall be prepared and placed in strict accordance with the following specifications and plans, and the instruc- tions of the engineer under them. Cement. The cement shall be of some standard brand of Portland cement, satisfactory to the engineer in charge. No cement shall be used which, when tested, fails to conform with the United States Government specifications for Portland cement, as contained 4n Circular 33 of the Bureau of Standards. Cement shall be delivered in sacks of 94 pounds net weight, and each sack shall be considered as having a volume of 1 cubic foot. Cement which contains lumps or has been dam- aged in any way by exposure to the weather or by other cause shall be rejected. Sand. The sand shall consist of dry, clean, sharp quartz grains, and shall not contain more than 5 per cent of clay, loam, or other foreign materials. The grains shall be well graded and of such size that all will pass a i^i-inch mesh screen, and not more than 20 per cent will pass a No. 50 sieve. Coarse Aggregate. The coarse aggregate may consist of either broken stone or gravel. Stone shall be sound, hard, and tough, and broken to the sizes hereinafter specified, and when used shall be free from foreign material. No weathered or disintegrated ma- ♦Prepared by Charles H. Moorefield, Highway Engineer, Office of Public Roads, Washington, D. C, and published in BuUetin No. 45 of that office. (214) Concrete Boads and Paveiiients. 215 terial shall be used. Gravel shall be composed of hard, sound, durable particles of stone, thoroughly clean and well graded in size between the limits specified below. Classes A, B, and C. — Unless otherwise specially pro- vided, there shall be three classes of concrete, known as class A, class B, and class C. Class A concrete shall consist (by volume) of 1 part of cement, 2 parts of sand, 4 parts of coarse aggregate, and water- All of the coarse aggregate shall be retained on a 14-inch mesh screen and shall pass a 1-inch mesh screen. Not more than 75 per cent shall be retained on a i/^-inch mesh screen, and not more than 75 per cent shall pass such a screen. Class B concrete shall consist (by volume) of 1 part of cement, 2^2 parts of sand, 5 parts of coarse aggregate, and water. All of the coarse aggregate shall be retained on a i^-inch mesh screen and shall pass a li/^-inch mesh screen. Not more than 75 per cent shall be retained on a %-inch mesh screen, and not more than 75 per cent shall pass such a screen. Class C concrete shall consist (by volume) of 1 part of cement, 3 parts of sand, 6 parts of coarse aggregate, and water. All of the coarse aggregate shall be retained on a i^-inch mesh screen, and shall pass a 2i/^-inch mesh screen. Not more than 75 per cent shall be retained on a 1^/4 -inch mesh screen, and not more than 75 per cent shall pass such a screen. Mixing. The cement and sand shall first be thoroughly mixed dry in the proportions specified, on a proper mixing platform. Sufiicient clean water shall then be admixed to produce a pasty mortar. To the mortar thus prepared shall be added the proper proportion of coarse aggregate previously drenched with water, and the whole shall be mixed until every particle of the coarse aggregate is thoroughly coated with mortar. Instead of the above method, a mechanical mixer of approved type may be employed. Size of Batch. Concrete shall be mixed in batches of such size that the entire batch may be placed in the forms by the force em- ployed within 45 minutes from the time that the first water is applied. No concrete is to be prepared from mortar which has taken an initial set and would require retempering. Placing. All concrete shall be carefully deposited in place and never allowed to fall from a height greater than five feet. Concrete shall never be deposited in running water, and when deposited in still water it shall be carefully lowered into 216 Concrete Roads and Pavements. place by means of a chute or by some other approved method. As fast as concrete is put into place, it shall be thor- oughly tamped in layers not more than six inches thick, and the portion next to the forms shall be troweled by using a spade or by other means to bring the mortar into thorough contact with the forms. Concrete shall not be deposited when the temperature of any of the materials composing it is below 35° F., and if during the progress of the work freezing temperature threatens or is predicted by the United States Weather Bureau, proper precautions shall be taken to protect from freezing all concrete laid within the four preceding days. Forms. Forms shall be so constructed as to continue rigidly in place during and after depositing and tamping the concrete. If during the placing of the concrete the forms show signs of bulging or sagging at any point, that portion of the con- crete causing the distortion shall be immediately removed and the forms properly supported before continuing the work. The amount of concrete to be removed shall be determined by the engineer, and the contractor shall receive no extra compensation on account of the extra work thus occasioned. Forms for exposed surfaces shall be constructed of dressed lumber. All forms shall be left in place not less than 36 hours, and all supporting forms not less than 10 days after the con- crete has been deposited. These periods may be increased at the discretion of the engineer in charge. It is understood that all prices for concrete masonry shall include furnishing all materials and properly constructing all necessary forms. Joints. When the work of laying concrete is to be interrupted for a period greater than 1 hour and there are no reinforcing rods projecting, provision for a joint shall be made in the following manner: Square timbers 8 inches by 8 inches, or some other suitable size approved by the engineer, shall be bedded in the concrete throughout the length of the course for one-half their thickness and allowed to remain until the concrete has taken its initial set. When the work of laying concrete is resumed, the timbers shall be removed and the surface thoroughly wet. No joints will be permitted in reinforced concrete beams, and in floor slabs the joints shall be vertical and parallel to the main reinforcing bars. Finish. Forms covering surfaces of the concrete masonry which are to be exposed shall be removed immediately after the Concrete Roads and Pavements. 217 expiration of the period of time necessary for such forms to remain in place, as fixed by the engineer, and all crevices which may appear shall be filled with 1:2 cement mortar. These surfaces shall then be finished with 1:2 cement mortar and a wooden float, so as to present a smooth, neat ap- pearance. Reinforced Concrete. All reinforced arches, beams, floors, parapets, guard rails, and all concrete masonry measuring less than 9 inches in thickness shall be made of class A concrete, unless other- wise specified on the drawings or directed by the engineer in writing. Abutments and Wing Walls. Unless otherwise specified on the drawings or in writ- ing by the engineer, class B concrete shall be used for all abutments and wing walls, the thickness of which is not less than 9 inches- Footings and Cut-Off Walls. Class C concrete shall be used for all footings and cut-off walls, unless otherwise specified on the plans or directed in writing by the engineer. Steel for Reinforced Concrete. Unless otherwise specified on the drawings, all reinforc- ing steel shall consist of bars which have been deformed in some approved manner. No plain bars will be permitted except as shown on the drawings or directed in writing by the engineer. The steel bars shall have the net sectional area and be placed in the exact positions indicated on the drawings. Unless otherwise specified on the drawings or in writing by the engineer, all reinforcing bars shall be of medium steel having an elastic limit of not less than 35,000 pounds per square inch, and shall be sufficiently malleable to withstand bending cold with a radius equal to twice the diameter or thickness of the bar through 180° without fracture. When placed in the concrete, the reinforcing steel shall be free from grease, dirt, and rust, and it shall be the duty of the contractor to provide means for properly cleaning the steel. Thorough contact of the concrete with every portion of the surface of the steel shall be obtained. Splicing Reinforcing Bars. Unless otherwise specified on the drawings or in writing by the engineer, necessary splices in reinforcing bars shall be effected by overlapping the ends of the bars a distance equal to forty times their thickness or diameter. APPE^TDix K. SPECIFICATIONS OF NATIONAL ASSOCIATION OF CEMENT USERS. SIDEWALKS. Materials. 1. Cement. — The cement shall meet the requirements of the Standard Specifications for Portland Cement of the American Society for Testing Materials and adopted by this Association. Standard No. 1. 2. Fine Aggregate. — Fine aggregate shall consist of sand, crushed stone or gravel screenings, graded from fine to coarse and passing, when dry, a screen having ^-inch diameter holes; shall be preferably of silicious material, clean, coarse, free from dust, soft particles, loam, vegetable or other deleterious matter, and not more than 3 per cent shall pass a sieve having 100 meshes per linear inch. Fine aggregate shall be of such quality that mortar composed of one part Portland cement and 3 parts fine aggregate by weight, when made into briquettes will show a tensile strength at least equal to the strength of 1:3 mortar of the same consistency made with the same cement and Standard Ottawa sand. In no case shall fine aggregate containing frost or lumps of frozen material be used. 3. Coarse Aggregate. — Coarse aggregate shall consist of inert materials such as crushed stone or gravel, graded in size, retained on a screen having 14 -inch diameter holes; shall be clean, hard and durable; free from dust, vegetable or other deleterious matter, and shall contain no soft, flat or elongated particles. In no case shall coarse aggregate con- taining frost or lumps of frozen material be used. The maxi- mum size of coarse aggregate shall be such as to pass a 114 -inch ring. 4. Natural Mixed Aggregates. — Natural mixed aggre- gates shall not be used as they come from the deposit, but shall be screened and remixed to agree with the proportions specified. 5. Sub-base. — Only clean, hard, suitable material, not exceeding 4 inches in the largest dimensions shall be used. 6. Water. — Water shall be clean, free from oil, acid, alkali or vegetable matter. 7. Coloring. — If artificial coloring material is required, only mineral colors shall be used. 8. Reinforcing Metal. — The reinforcing metal shall meet (218) Concrete Roads and Paveme7its. 219 the requirements of the Standard Specifications for Steel Re- inforcement adopted March 16, 1910, by the American Rail- way Engineering Association. Sub-Grade. 9. Slope. — The sub-grade shall have a slope toward the curb of not less than Vz inch per foot. 10. Depth,* — (a) The sub-grade shall not be less than 11 inches below the finished surface of the walk. (b) The sub-grade shall not be less than 5 inches below the finished surface of the walk. 11. Preparation. — All soft and spongy places shall be removed and all depressions filled with suitable material which shall be thoroughly compacted in layers not exceeding 6 inches in thickness. 12. Deep Fills. — When a fill exceeding 1 foot in thick- ness is required to bring the work to grade, it shall be made in a manner satisfactory to the engineer. The top of all fills shall extend beyond the walk on each side at least 1 foot, and the sides shall have a slope not greater than 1 to 1%. 13. Drainage. — When required, a suitable drainage sys- tem shall be installed and connected with sewers or other drains indicated by the engineer. Sub-Base.* 14. Width. — Thickness. — On the sub-grade shall be spread a suitable material as hereinbefore stated which shall be thoroughly rolled or tamped to a surface at least 5 inches below the finished grade of the walk. On the fills, the sub- base shall extend the full width of the fill and the sides shall have the same slope as the sides of the fill. 15. Wetting. — While compacting the sub-base, the ma- terial shall be kept thoroughly wet and shall be in that con- dition when the concrete is deposited. Forms. 16. Materials. — Forms shall be free from warp and of sufficient strength to resist springing out of shape. 17. Setting. — The forms shall be well staked or other- wise held to the established lines and grades and their upper edges shall conform to the established grade of the walk. 18. Treatment. — All wood forms shall be thoroughly wetted and metal forms oiled before depositing any material against them. All mortar and dirt shall be removed from forms that have been previously used. Construction. 19. Size of Slabs. — The slabs or independently divided *Note. — When a sub-base is required, eliminate Paragraph 10 (b). When a sub-base is not required, eliminate Paragraphs 5 and 10 (a). Unless Paragraph 10 (a) is eliminated, 10 (b) is void. 220 Concrete Roads and Pavements. blocks when not reinforced shall have an area of not more than 36 square feet and shall not have any dimension greater than 6 feet. Larger slabs shall be reinforced as hereinafter specified. 20. Thickness of Walk. — The thickness of the walk should not be less than 5 inches for residence districts, and not less than 6 inches for business districts. 21. Width and Location of Joints. — A i/^-inch expansion joint shall be provided at least once in every 50 feet. 22. Joint Filling. — The expansion joint filler shall be a suitable elastic waterproof compound that will not become soft and run out in hot weather, nor hard and brittle and chip out in cold weather. 23. Protection of Edges. — Unless protected by metal, the upper edges of the concrete shall be rounded to a radius of 1/^ inch. Measuring and Mixing. 24. Measuring. — The method of measuring the materials for the concrete, including water, shall be one which will insure separate uniform proportions at all times. A sack of Portland cement (94 lbs. net) shall be considered 1 cubic foot. 25. Machine Mixing. — When the conditions will permit, a machine mixer of the type that insures the uniform pro- portioning of the materials throughout the mass, shall be used. The ingredients of the concrete or mortar shall be mixed to the desired consistency and the mixing shall con- tinue until the cement is uniformly distributed and the mass is uniform in color and homogeneous. 26. Hand Mixing. — When it is necessary to mix by hand, the materials shall be mixed dry on a watertight platform until the mixture is of uniform color, the required amount of water added and the mixing continued until the mass is uni- form in color and homogeneous. 27. Retempering, that is, remixing mortar or concrete that has partially hardened with additional water, will not be permitted. TWO-COURSE WALKS. Base. 28. Proportions. — The concrete shall be mixed in the proportion by volume of 1 sack Portland cement, 2^ cubic feet fine aggregate and 5 cubic feet coarse aggregate. 29. Consistency. — The materials shall be mixed wet enough to produce a concrete of a consistency that will flush readily under slight tamping, but which can be handled with- out causing a separation of the coarse aggregate from the mortar. 30. Placing. — After mixing, the concrete shall be handled on Crete Roads and Pavements. 221 rapidly and the successive batches deposited in a continuous operation completing individual sections. Under no circum- stances shall concrete be used that has partially hardened. The forms shall be filled and the concrete struck off and tamped to a surface the thickness of the wearing course below the established grade of the walk. After the concrete has been thoroughly tamped against the cross forms, they shall be removed and the material for the adjoining slab de- posited so as to preserve the joint. Workmen shall not be permitted to walk on the freshly laid concrete, and if sand or dust collects of the base it shall be carefully removed before the wearing course is applied. 31. Reinforcing. — Slabs having an area of more than 36 square feet, or having any dimension greater than 6 feet, shall be reinforced with wire fabric or with plain or deformed bars. The cross sectional area of metal shall amount to at least 0.041 square inches per lineal foot. The reinforcing metal shall be placed upon and slightly pressed into the con- crete base immediately after the base is placed. Reinforcing metal shall not cross joints and shall be lapped sufficiently to develop the strength of the metal. Wearing Course. 32. Proportions. — The mortar shall be mixed in the man- ner hereinbefore specified in the proportion of 1 sack Port- land cement and not more than 2 cubic feet of fine aggregate. 33. Consistency. — The mortar shall be of a consistency that will not require tamping, but which can be easily spread into position. 34. Thickness. — The wearing course of walk in residence districts shall have a minimum thickness of % of an inch, and in business districts a minimum thickness of 1 inch. 35. Placing. — The wearing course shall be placed im- mediately after mixing and in no case shall more than 50 minutes clause between the time the concrete for the base is mixed and the time the wearing course is placed. 36. Finishing. — After the wearing course has been brought to the established grade, it shall be worked with a wood float in a manner that will thoroughly compact it. When required, the surface shall be troweled smooth, but excessive working with a steel trowel should be avoided. The slab markings shall be made in the wearing course directly over the joints in the base with a tool which will completely separate the wearing course of adjacent slabs. If excessive moisture occurs on the surface, it must be taken up with a rag or mop, and in no case shall dry cement or a mixture of dry cement and sand be used to absorb this moist- ure or to hasten the hardening. Unless protected by metal, the surface edges of all slabs shall be rounded to a radius of about V2 inch. 222 Concrete Roads and Pavements. 37. Coloring. — If artificial coloring is used, it must be incorporated with the entire wearing course, and shall be mixed dry with the cement and aggregate until the mixture is of uniform color. In no case shall the amount of coloring used exceed 5 per cent of the weight of the cement. ONE-COURSE WALK. The general requirements of the specifications covering two-course work will apply to one-course work with the fol- lowing exceptions: 38. Proportions. — The concrete shall be mixed in the proportion of 1 sack Portland cement to not more than 2 cubic feet of fine aggregate, and 3 cubic feet of coarse aggre- gate passing a 1-inch ring. 39. Placing and Finishing. — The form shall be filled, the concrete struck off and the coarse particles forced back from the surface, and the work finished in the usual way. 40. Reinforcing. — When a single course walk is to be reinforced, the metal shall be placed at the middle of the section. The minimum amount of metal shall be as speci- fied in paragraph 31. Protection. 41. Treatment, — As soon as the concrete has hardened sufficiently to prevent being pitted, the surface of the walk shall be sprinkled with clean water and kept wet for at least 4 days. The walk shall not be opened to traffic until the engineer so directs. 42. Temperature Below 35° F. — If at any time during the progress of the work the temperature is, or in the opinion of the engineer will within 24 hours drop to 35 degrees Fahrenheit, the water and aggregate shall be heated and pre- cautions taken to protect the work from freezing for at least 5 days. In no case shall concrete be deposited upon a frozen sub-grade or sub-base. APPEA^DIX L. SPECIFICATIONS OF NATIONAL ASSOCIATION OF CEMENT USERS. CURB AND GUTTER. Materials. 1. Cement. — The cement shall meet the requirements of the Standard Specifications for Portland Cement of the Ameri- can Society for Testing Materials and adopted by this As- sociation. (Standard No. 1.) 2. Fine Aggregate. — Fine aggregate shall consist of sand, crushed stone or gravel screenings, graded from fine to coarse, and passing, when dry, a screen having 14 -inch diameter holes; shall be preferably of silicious material, clean, coarse, free from dust, soft particles, loam, vegetable or other deleterious matter, and not more than 3 per cent shall pass a sieve having 100 meshes per linear inch. Fine aggregate shall be of such quality that mortar composed of 1 part Portland cement and 3 parts fine aggregate by weight when made into briquettes will show a tensile strength at least equal to the strength of 1:3 mortar of the same con- sistency made with the same cement and Standard Ottawa sand. In no case shall fine aggregate containing frost or lumps of frozen material be used. 3. Coarse Aggregate. — Coarse aggregate shall consist of inert materials such as crushed stone or gravel graded in size, retained on a screen having i^-inch diameter holes; shall be clean, hard and durable, free from dust, vegetable or other deleterious matter, and shall contain no soft, flat or elongated particles. In no case shall coarse aggregate containing frost or lumps of frozen material be used. The maximum size of coarse aggregate shall be such as to pass a 114 -inch ring. 4. Natural Mixed Aggregates. — Natural mixed aggre- gates shall not be used as they come from the deposit, but shall be screened and remixed to agree with the proportions specified. 5. Sub-Base. — Only clean, hard, suitable materials, not exceeding 4 inches in the largest dimension shall be used. 6. Water. — Water shall be clean, free from oil, acid, alkali or vegetable matter. 7. Coloring. — If artificial coloring material is required, only mineral colors shall be used. (223) 224 Concrete Roads and Pavements. Sub-Grade. 8. Depth Below Grade. — (a) Concrete Curb — When a sub-base is required, the sub-grade shall not be less than 30 inches below the established grade of the curb. (b) Concrete Curb and Gutter. — When a sub-base is re- quired, the sub-grade shall not be less than 11 inches below the established grade of the gutter. 9. Preparation. — All soft and spongy places shall be re- moved and all depressions filled with suitable material, which shall be thoroughly compacted in layers not exceeding 6 inches in thickness. 10. Deep Fills. — When a fill exceeding 1 foot in thick- ness is required to bring the work to grade, it shall be made in a manner satisfactory to the engineer. 11. Drainage.— When required, a suitable drainage sys- tem shall be installed and connected with sewers or other drains indicated by the engineer. Sub-Base. 12. Thickness, (a) Concrete Curb. — On the sub-grade shall be spread a material as hereinbefore specified, which shall be thoroughly rolled or tamped to a surface at least 24 inches below the established grade of the curb. (b) Concrete Curb and Gutter. — On the sub-grade shall be spread a material as hereinbefore specified, which shall be thoroughly rolled or tamped to a surface at least 6 inches below the established grade of the gutter. 13. Wetting. — While compacting the sub-base, the ma- terial shall be kept thoroughly wet and shall be in that con- dition when the concrete is deposited. Forms. 14. Materials. — Forms shall be free from warp, and of sufficient strength to resist springing out of shape. 15. Setting. — The forms shall be well staked or otherwise held to the established lines and grades, and their upper edges shall conform to the established grade of the curb or curb and gutter. 16. Treatment. — All wood forms shall be thoroughly wetted and metal forms oiled before depositing any material against them. All mortar and dirt shall be removed from forms that have been previously used. Construction. 17. Dimension of Curb. — The section of the curb shall conform with that shown in Fig. 1. The thickness at the base shall not be less than 12 inches, and at the top not more than G inches, with a batter on the street side of 1 to 4. 18. — Dimensions of Curb and Gutter. — The sections of the combination curb and gutter shall conform with that shown in Fig. 2. The depth of the back of the curb shall Concrete Roads and Pavements, 225 not be less than 12 inches and the depth of the face not less than 6 inches. The breadth of the gutter shall not be less than 16 inches nor more than 24 inches. 19. Size of Sections. — The curb and gutter shall be di- vided into sections not less than 5 nor more than 8 feet long by some method which will insure the complete separation of the sections. 20. Section at Street Corners. — The construction of the combination curb and gutter at street corners shall conform with that shown in Figure 3. The radius of the curb shall not be less than 6 feet. 21. Width and Location of Joints. — A i/^-inch expansion joint shall be provided at least once in every 150 feet. 22. Joint Filler. — The expansion joint filler shall be a suitable, elastic, waterproof compound that will not become soft and run out in hot weather, nor hard and brittle and chip out in cold weather. 23. Protection of Edges.^Unless protected by metal, the upper edges of the concrete shall be rounded to a radius of ^2 inch. Measuring and Mixing. 24. Measuring. — The method of measuring the materials for the concrete, including water, shall be one which will in- sure separate uniform proportions at all times. A sack of Portland cement (94 pounds net) shall be considered 1 cubic foot. 25. Machine Mixing. — When the conditions will permit, a machine mixer of a type which insures the uniform pro- portioning of the materials throughout the mass, shall be used. The ingredients of the concrete or mortar shall be mixed to the desired consistency and the mixing shall con- tinue until the cement is uniformly distributed and the mass is uniform in color and homogeneous. 26. Hand Mixing. — When it is necessary to mix by hand, the materials shall be mixed dry on a watertight platform until the mixture is of uniform color and the required amount of water added, and the mixing continued until the mass is uniform in color and homogeneous. 27. Retempering, that is remixing mortar or concrete that has partially hardened, with additional water, will not be permitted. TWO-COURSE CURB AND CURB AND GUTTER. Base. 28. Proportions. — The concrete shall be mixed in the proportion of 1 sack Portland cement, 2^ cubic feet fine aggre- gate, and 5 cubic feet coarse aggregate. 29. Consistency. — The materials shall be mixed wet enough to produce a concrete of a consistency that will flush 226 Concrete Roads and Pavements. readily under slight tamping, but which can he handled with- out causing a separation of the coarse aggregate from the mortar. 30. Placing. — After mixing, the concrete shall be handled rapidly and the successive batches deposited in continuous operation completing individual sections. Under no circum- stances shall concrete be used that has partially hardened. The gutter forms shall be filled and the concrete struck off and tamped to a surface the thickness of the wearing course below the established grade of the gutter. The concrete for the curb shall be placed and tamped so as to permit of the application of the required wearing course to the face and top so as to bring the work to the established line and grade of the curb. The work shall be executed in a manner which will insure perfect joints between abutting sections. Work- men shall not be permitted to walk on freshly laid concrete, and if sand or dust collects on the base, it shall be carefully removed before the wearing course is applied. Wearing Course. 31. Proportions. — The mortar shall be mixed in the man- ner hereinbefore specified in the proportion of 1 sack Portland cement and not more than 2 cubic feet of the fine aggregate. 32. Consistency. — The mortar shall be of a consistency that will not require tamping, but which can be easily spread into position. 33. Thickness. — The wearing course of the gutter and top and face of the curb shall have a minimum thickness of % of an inch. 34. Placing. — The wearing course shall be placed imme- diately after mixing, and in np case shall more than 50 min- utes elapse between the time the concrete for the base is mixed and the time the wearing course is placed. 35. Finishing. — After the wearing course has been brought to the established line and grade, it shall be worked with a wood float in a manner which will thoroughly compact it. When required, the surface shall be troweled smooth, but excessive working with a steel trowel shall be avoided. The section markings shall be made in the wearing courses di- rectly over the joints in the base with a tool which will com- pletely separate the wearing courses of adjacent sections. If excessive moisture occurs on the surface, it must be taken up with a rag or mop, and in no case shall dry cement or a mix- ture of dry cement and sand be used to absorb this moisture or to hasten the hardening. The edge of the curb on the street side and the intersection of the curb and gutter shall be rounded to a radius of about iy2 inches. All other edges shall be rounded to a radius of % inch unless protected by metal. 36. Coloring. — If artificial coloring is used, it must be in- Concrete Roads and Pavements. 211 corporated with the entire wearing course and shall be mixed dry with the cement and aggregate until the mixture is of uniform color. In no case shall the amount of coloring used exceed 5 per cent of the weight of the cement. One-Course Curb and One-Course Curb and Gutter. The general requirements of the specifications covering two-course work will apply to one-course work, with the fol- lowing exceptions: 37. Proportions. — The concrete shall be mixed in the pro- portion of 1 sack Portland cement and not more than 2 cubic feet of fine aggregate, and 3 cubic feet of coarse aggregate passing a 1-inch ring. 38. Placing and Finishing. — The forms shall be filled, the concrete struck off and the coarse particles forced back from the surface, and the work finished in usual way. Protection. 39. Treatment. — As soon as the concrete has hardened sufficiently to prevent being pitted, it shall be sprinkled with clean water and kept wet for at least 4 days. The work shall not be opened to traffic until the engineer so directs. 40. Temperature below 35° F. — If at any time during the progress of the work, the temperature is, or in the opinion of the engineer will within 24 hours drop to 35 degrees Fahrenheit, the water and aggregates shall be heated and precautions taken to protect the work from freezing for at least 5 days. In no case shall concrete be deposited upon a frozen sub-grade or sub-base. CD CD 00 Q LU cn _l CQ ? CO UJ o o UJ o CQ D O I— O o CD 39 ^ r aO < a 50 Cents Per Year Devo-lcd to C« THE A LL developments in regard to Concrete Roads and Pavements are carefully recorded in this journal. Three Years for $1.00 THE CEMENT ERA is the favor- ite Cement Journal. Why? Because it is out on the skirmish line all the time — fighting your battles, keeping you posted on new develop- ments, telling you how to make more money out of your business. It is not written by office theorists, but by men who are actually in close touch with the field. The best journal for the man who wants to keep in touch with the progress of concrete road making. The Cement Era Publishing Co. 1207 Morton Building CHICAGO Cement Pipe and Tile By E. S. HANSON Table of Contents I. Introduction. II. Advantages of Cement for Pipe and Tile. III. Concrete Pipe Sewers. IV. Pipe for Pressure Service. V. Concrete Pipe for Culverts. VI. Establishing a Plant. VII. Materials Required. VIII. Methods of Manufacture. IX. Curing. X. The Matter of Costs. XI. Some Tests of Pipe and Tile. XII. Machines and Systems on the Market. PRICE $1.00 THIS VOLUME covers a field all its own. The rapid development of this branch of the industry has given rise to many calls for information along these lines — and this book is the result. The author has perhaps visited more plants for the manu- facture of these products than any other one person, and has spent much time in investigating the subject on which he writes. He has endeavored to answer the many questions which come up in regard to these subjects and to answer them from the actual experi- ence of men in the business. The Cement Era Publishing Co. 1207 Morton Building CHICAGO KENT PRECISION MIXERS Produce concrete of the highest quahty at the lowest possi- ble cost. They are the most economical mixer made for mixing concrete for street paving, curb and gutter, highway bridges, foundations, retaining walls, etc. The illustration show our 1913 model with roll over hoppers, removable feed plate, reversible mixing shaft, spur gear drive, also with traction operating in either direction. It is the Last Word in Concrete Mixers Write for catalog, giving full information, to THE KENT MACHINE COMPANY 318 North Water Street KENT, OHIO Baker Armored Joints for Concrete Roads and Pavements These Joints, and the Installation Bar with which they are so readily placed, are the invention of a practical builder of concrete roads and pavements. They have been installed in about a million and a half yards of concrete roadway, notably the work in Wayne County, Michigan, and have never failed. Here is what Mr. Edward N. Hines, member of the Wa^r\e County Highway Commission, sa^s of them: "The only surface repair required on our concrete roads has been on the roads first constructed, where the joints were not protected with the armor plates. "By the use of armor p'ates we have practically over- come the wear at the joints, which are the weakest points in the concrete road, besides securing a smooth, even, continuous finish." These joints consist of two armor plates of 3/16 inch soft steel, 23^2 inches wide, provided with shear mem- bers which tie them securely to the concrete. Between these armor plates, and extending to the subgrade, are one or more thicknesses of asphalt felt. The joints are curved to the crown of the roadway, and are assembled by means of the special Installation Bar furnished on each job. This bar insures accurate and economical placing. Baker Joints add years to the life of a roadway, at a cost of only about 5 cents per square yard. The R. D. BAKER COMPANY 73 HOME BANK BUILDING DETROIT. MICHIGAN 1 en 3 Critical Inspection Fails to T)evelop a Defect in Our Wheelbarrows OR SCRAPERS BULL TROG WHEELBARROWS UILT r OR T f ORK The Toledo Wheelbarrow Co, Wheelbarrows and Scrapers Chicago, 111. 337 River Street Toledo, O., U.S.A. Hassam Pavement on Massachusetts State Highway at Spencer, Mass. Laid in 1906. Photo 1912 Hassam Pavement is the ideal pavement for all conditions. It com- bines the maximum strength of a necessary foundation and embodies about 20% more stone as a wearing material throughout the entire mass than any other known method of concrete construction. Our Compressed Concrete with Bituminous Wearing Surface is the best form of pavement for all medium and light traffic, it is noiseless, re- silient and sanitary and requires but little expenditure for repairs. For heavily travelled streets our Hassam Granite Block Wearing Surface is the best known form of pavement. A handsome hand book on Hassam Pavements will be sent on request Hassam Paving Company Worcester, Mass. GOOD ROADS NEED GOOD BRIDGES LUTEN UNIT TRUSSES GIVE To the ENGINEER— Insmsince that the steel goes into the concrete as he designed it. To the CONTRACTOR— A reinforcement at a reasonable cost and a unit easily handled. To the WORKMAN— Ease in work and the certainty that it is correctly placed in the concrete. The National Concrete Company INDIANAPOLIS. INDIANA Write for Booklet " H " giving tables and Specifications for Highway Bridges. The SIMPLEX Improved Mixer combines the good features of both batch and continuous mixers in one machine, and eliminates the faults of both. The best feature of Batch Mixers is the rolling of the materials. The greatest advantage of the Continuous Mixer is the automatic measuring and feeding of the materials. The SIMPLEX has a powerful low-down steel frame and trucks, a three-part hopper, and has any capacity up to ten yards per hour. Is fully guaranteed, and sent on trial. Write for catalog and full information. THE MILES MANUFACTURING COMPANY 316 E. Franklin Street -:- JACKSON, MICHIGAN Studying the National Problem Good Roads Leads to the inevitable con- clusion that satisfactory roads must be reasonable in cost, low in maintenance charges and per- manent. Large expenditures for country road and city street improvements are not justified when the pavements afford only temporary relief — when they are costly in upkeep and obsolete under traffic conditions of today. In Wayne County (Detroit) Michigan concrete has been adopted as the type of road best answering modern re- quirements. Concrete makes ideal roads — low in initial cost — free fi-om heavy maintenance charges, durable, dustless, clean and permanent. Write us for free booklets, describing CON- CRETE ROADS— Fifth and Sixth Annual Re- ports of the Wayne County Road Commissioners Universal Portland Cement Co. Alpha Portland Cement The Recognized Standard American Brand Annual Output; 7,000.000 Barrels Works : Two plants at Alpha, N. J., 70 miles west of New York City, on Lehigh Valley R. R. Two plants at Martins Creek, Pa., 80 miles west of New York City, on P. R. R., D. L. & W. R. R., and L. & N. E. R. R. One plant at Manheim. W. Va., on M. & K. and B. & O. R. R. One plant at Catskill, N. Y., 100 miles north of New York City, on N. Y. C. & H. R. R. R. and Hudson River. Boat shipments direct to all Barge Canal points. Atlantic Coast and Foreign Ports. ALPHA is guaranteed to pass all Standard, State and Government Specificafions Used Extensively in State Highway Work Prompt Shipments Guaranteed Alpha Portland Cement Co. General Office EASTON, PENNSYLVANIA Branch Offices Boston Savannah Buffalo Pittsburgh Chicago Baltimore Philadelphia New York Could you reduce your charging labor to 1 man and still do the same amount of work? YOU COULD IF YOU HAD '^The STANDARD'' Mixer With CART CHARGER The greatest time and money saving Road Paving Mixer ever offered to the contractor. The materials for one entire batch are loaded in carts at the material piles and pulled to the mixer by a simple hoist with cable attachment. The carts are guided to and from the mixer by one man. Only one operation required to charge the mixer. No high charging platform or complicated side loader. Cut your charging labor 80% and do twice the work. Can be equipped with distributing chute and reverse traction. SEMI AUTOMATIC DISCHARGE— OPEN DRUM. Let us show you how we have saved thousands of dollars for hundreds of contractors. " The STANDARD " regular machines have a low charging platform only two feet high and is attached to the mixer. The Standard Scale & Supply Co. YOU CAN EASILY DO MORE WORK, IN LESS TIME, AT BIGGER PROFITS because with the Koehring Special Street Paving Mixer one man thoroughly mixes, delivers to a distance of 20 or 30 feet and spreads the full contents of the drum in one minute's time without leaving the machine The bucket immediately and auto- matically returns to the drum to repeat the operation, thereby producing an almost continuous flow of concrete from the ma- chine to any desired spot of the work on either side. If you want to win more contracts, and if you desire to more satisfactorily and speedily complete each job at bigger profits, to yourself, get a Roehring. Koehring Machine Company, Milwaukee, Wis. This is the Koehring Street Paving Mixer equipped with twenty-foot special concrete delivery boom and bucket — the pioneer and most satis- factor\ street mixer \n the world — often imitated but never duplicated. THE KOEHRING PRODUCES MORE AND BETTER CONCRETE Eor Less Money and with Less Cement BECAUSE with every rotation of the Koehring drum the entire batch is many times cut through from ihe bottom, pressed and folded over upon itself with a criss-cross, kneading, squeezing motion and a raking from end-to-end action that means more thorough and more rapid mixing than any other machine on the market. The Koehring does three kinds of mixing at once — and every one diametrically opposed to the other, thus causing a cataract flow from top and sides against the inner end of the discharge chute plate— always at right angles to the other mixing— thus creating a better mix than is possible through any other method and consequently effecting a greater saving in cement. The Koehring is the only machine that does it because it is the only machiae that can do it. Illustrated booklet on request. City Pavements or Country Roads of concrete or hot bitum- inous mixtures can be Inid at a greater mar- fin of profit with a Koehring Street Paving Mixer. KOEHRING MACHINE COMPANY GENERAL OFFICES AND WORKS MILWAUKEE. WISCONSIN, The Koehring Street Panng Mixer holds the biggest records. Built in three sizes and two styles— for concrete only or both concrete and bituminized mixturea* Ever Wonder Why Cube Mixers Were Selected for the Wayne O County Concrete Road Jobs • Remember there are nine Austin Improved Cube Special Street Mixers in the main mixing plant, on this most notable concrete road construction in America, and here's the very good reason why they were selected by the commission: "We have purchased mixers which are provided with a boom eighteen feet long, which extends to the rear, and can be easily revolved about the axis to positions varying 180 degrees. On this boom a bucket is run back and forth, and in it the mixing product is con- veyed from the mixer to the road. On account of the movability of the boom, the concrete is deposited wherever wanted, and the expense of six or eight men to haul the concrete in carts from the machine to the place required is reduced to two." Men such as these, acting for the public interest and with the entire market at their disposal, do not buy a mixer with- out investigation. Our mixer has probably been subjected to more exacting tests than any other machine on the market; and the more it is tested, the more it is used. The Austin Cube Drum of the Austin Improved Cube Mixer gives it a dis- tinct mixing principle. This CUBE principle as applied to concrete mixing was one of the first ever devised and nothing else has been able to excel it in simplicity, thoroughness of mix, rapidity and ease of handling. The entire absence of internal mechanism prevents any possibility of clogging and renders the drum easy to clean. In an AUSTIN CUBE DRUM the batch is treated throughout a s a unit. Not a parti- cle escapes. The whole batch is sifted six times in each revolution of the drum. The mixing is done by kneading and not by stirring. Made in sizes from 2^ to 64 cubic feet. Send for Catalog No, 20 Municipal Engineering & Contracting Co. NEW YORK OFFICE, 90 West Street Main Office, Railway Exchange CHICAGO. ILL. New England Agent Southwestern Agent Dyar Supply Co. - - - - Cambridge, Mass. Wyle Mfg. Co. ------ Oklahoma City Western Pennsylvania Agent: J. S. Beckwith Pittsburgh. Pa. Pacific Coast Aaents- The Lansing Co. - ----- San Francisco PaciticUoast Agents. The Beebe Co. -------- Portland AGENTS WANTED IN OPEN TERRITORY BLAW STEEL FORMS For Sidewalk Curb, and Curb and Gutter Construction will increase your PROFITS 30 % Some Reasons WHY RT AW ^TFFT FORM^ ^ill not wear out. They are DI^/ifT OlLl^L runiTlJ simple, light but very rigid. Easy to operate. No complicated parts to lose or get out of order. Easily and quickly set up. Can be taken away and moved forward to new position in about one-tenth the time and with about one-tenth the labor that it takes with the old method of wood Forms. No measuring or sawing. Perfect alignment obtained. No bracing required. Can be operated by unskilled labor. Lumber bill entirely eliminated. No maintenance expense. They are indestructible and will last for years. The same Forms can be used on Sidewalk Curb, and Curb and Gutter Construction. Write for Bulletin 47-A on Sidewalk, Curb and Gutter Construction We design and build Blaw Steel Forms for every type of Concrete Construction. BLAW STEEL CONSTRUCTION CO. General Offices — Pittsburgh, Pa. New York, 165 Broadway ChicagO, PeoplCS GaS Bldg. 7-Mile Concrete Road, Cedar Point, Ohio W. S. PACE, CHICAGO, CONTRACTOR, USING MEDUSA PORTLAND CEMENT ON THE CEDAR POINT SPEED- WAY, THE LONGEST CONCRETE ROADWAY IN OHIO Medusa Gray Portland Cement is guaranteed to be a high-testing Portland, passing standard specifications, and is unsurpassed in fineness, strength and uni- formity. Factories are located at Bay Bridge, O., Syracuse, Ind., and Dixon, 111., from which shipments can be made promptly. We solicit your inquiries for prices. 2,500,000 BARRELS MEDUSA GRAY PORTLAND CEMENT SOLD YEARLY Write for free samples and illustrated booklets of MEDUSA GRAY PORTLAND CEMENT MEDUSA WHITE PORTLAND CEMENT MEDUSA WATERPROOFING MEDUSA WATERPROOFED CEMENTS (Gray and White Portland) SANDUSKY PORTLAND CEMENT CO. SANDUSKY, OHIO PREPARING AN OLD ROAD FOR RE-SURFACING THE best, quicker and cheapest way is by means of a Huber Roller with Scarifier attached. You can hitch a grader on also if you wish, and do your scarifying and grading at the same time. Then detach the grader, raise the scarifier clear of ground, and use the roller to finish preparing the new surface. This is a proposition worth investigating by any road or ^reet contractor. The scarifier is operated by fteam power, an inde- pendent cylinder being placed beneath the boiler for that purpose. A ftraight lever close to operator's hand raises or lowers spikes. Adtion is instantaneous. THE HUBER MANUFACTURING CO., Marion, o. A SHALLOW CUT— A PERFECT GRADE— HANDLED AT A PROFIT THE MARION REVOLVING SHOVEL is now taking the place of hand- labor for road and street work. (Note the shallow cut and perfect grade in the above picture.) These small shovels can be operated by one man. They are self propell- ing, and mounted on either traction wheels or railroad trucks, as desired. Write for information THE MARION STEAM SHOVEL CO. MARION, OHIO, U. S. A. New York Atlanta Chicago WAINWRIGHT STEEIBOUND CONCRETE CURB HAS A RECORD OF FIFTEEN YEARS' USE "W4INWRIGHT PATENTS" WITHOUT A FAILURE ABSOLUTELY NON-BREAKABLE CHEAPER THAN GRANITE OVER FIVE MILLION FEET IN USE IN MORE THAN FOUR HUNDRED CITIES IN THE UNITED STATES THE WAINWRIGHT GALVANIZED STEEL CORNER BAR HAVING SOLID ROUNDED HEAD AND DOVETAILED WEB EXTENDING TWO INCHES INTO THE CON- CRETE ITS ENTIRE LENGTH, FORMING CONTINUOUS IN- TEGRAL ANCHORAGE, IS THE ONLY BAR THAT CAN BE DEPENDED ON TO PERMANENTLY RETAIN ITS PLACE IN CONCRETE. FROST WILL NOT DISPLACE THE WAINWRIGHT BAR AS IT WILL ANY BAR ANCHORED AT INTERVALS STEEL PROTECTED CONCRETE CO. REAL ESTATE TRUST BUILDING PHILADELPHIA, PA. We Build Universal and Eureka Crushers In 25 Sizes. Fully Guaranteed The Crushers cover every requirement in the crush- ing field. Both stationary plants and mounted outfits for Con- tractors and Road Building. Crushing from 3^ in. and finer to any desired size, with a capacity of from 5 to 250 tons per day. All machines adjusted to produce any desired size while in operation. We also manufacture a full line of standard elevators and screens. Write us your requirements, advising kind of material, size and amount required per day. Our proposion will interest you. ADDRESS Universal Crusher Company The tremendous enthusiasm shown in the Big-an-Little Mixers is indicative of the exceptional advantages which the Big-an-Little Mixer offers OUR LOW PRICES AMAZE THE "MIXER WORLD" Yes, there's big value in the Big-an-Little Mixer. It will increase your cement work profits and knock big holes in expense. A "Mix a Minute" whether large or small from this Big-an-Little Mixer- Equipped with loader if desired, which doubles capacity. Same device can also be used for hoisting, or is furnished on skids without power. It's built Hke a Battle Ship to wear forever — without the extras, the price boosting, useless features that do not add efficiency to the Mixer. It's sold under an Iron Clad Guarantee that is positive protection for you, and one price to all. It's not a big mixer. It's not a little mixer. Capacity per batch 43^ to 6 cu. feet. It's the mixer that will put dollars in your pocket and give perfect satis- faction for years. It's simple — compact, durable, good capacity and the price is right. THE JAEGER MACHINE CO. 216 West Rich Street :: COLUMBUS, OHIO MIXER DEPARTMENT Bull-Dog Batch Mixer No. 1-B being used on street work, putting in a Dollar- way concrete pavement, by Childs & Sa^vyer, Paving Contractors, Kendallville, Ind. The kind of mixer with the quaHty and the efficiency in it. One that is strongly built for wear and tear. Has many new features in charging, mixing and discharging. Not very often does one find quality combined with a very low price as in a Bull-Dog Batch Mixer. Made in four sizes, 34 yard up. ^^Crescent'^ Continuous Mixer has every advantage of the batch portant, profit-producing features, that could not be obtained in a batch mixer. Is the simplest, strongest, most practical and handy mixer on the market. Pro- portions accurately and mixes thoroughly. We guarantee it. Write for Catalogues Also Make " Crescent" |^ Concrete Sewer Pipe Molds mixer, and many more im- Raber & Lang Mfg. Coo 822 Mill Street Kendallville, Ind. MIXERS IN ALL STYLES AND SIZES the Batch Line WINNER MONEY MAKER HELPER We are specialists in the Concrete Machinery line, and if you are in need of a Mixer, Screen, Elevator, Tile or Culvert Molds we have them. Our Winner Mixer for its size can't be beat, and at the price of $150.00 it is by far the best Mixer for the money. Get our Prices and literature describing our line before buying and save money. Continuous line Perfection No. 1 Perfection No. 2 Combination with Elevator Perfection No. 1 THE CEMENT TILE MACHINERY CO 201 Rath St. WATERLOO, IOWA The Coltrin Continuous -Batch Mixer No. 12 Coltrin The Automatic Proportioning Hopper Delivers exact quantities of the different materials in per- fectly measured small batches every stroke of the feed. The Measuring Pockets are cleaned every stroke of the plunger. The Mixing Blades revolving in a steel shell cut through the material at the bottom and lift and pour it from the side same as the latest improved batch mixers. Has Direct Gear Drive— 2 Main Gear and 2 Pinions No Chains — No Sprockets — No Belt No Revolving Parts — No Springs — No Fillers Shipped anywhere on trial. The Knickerbocker Co., Jackson, Mich, Write for Catalog, When in search of a Simple and Durable Mixer look up the New Cream City Mixer The Efficient Kind BUILT IN FIVE SIZES These mixers are so light and compact that they can be easily drawn about by one horse, making it convenient to move them from place to place where a number of jobs are under way in different parts of the same locality. Each mixer is equipped with the latest style worm gear driven loaders. The drum is made of two semi-steel castings bolted together. The drum is driven by a center chain drive — the best drive known and requiring least power to operate. Write for Catalogue and Prices Cream City Equipment Co. 809 Majestic Building - Milwaukee, Wis. SENIOR B. MIXER PREDETERMINED ACCURATE MIXING All the material automatically meas- ured to the mixer, water added after the material is dry mixed and all the material given the same amount of mixing and a guaranty of uniform quality of concrete, is what you get with a U. S. Standard Concrete Mixer Every operation is mechanical and accu- rate, no guessing at proportions or mix- ing, with half the expenditure for labor. R. R. REED, Gen. Sales Agent ASHLAND, OHIO No "Break 'Downs with the Friction Thrives The Badger Concrete Mixer No. 6 9 cubic ft. load ma-. terial; 6 cubic feet finished batch. Batch Hopper hold- ing entire batch. Low charging platform. End discharge. Friction drive. Ample engine power, clutch for starting. The BADGER No. 3 Concrete Mixer Our Badger line includes Badger No.j, friction drive, a 3 cu. ft. batch mixer. This is a side discharge mixer on trucks and is most convenient for pulling about in building foundations, curbing, sidewalk and for small contracts. Also, the Badger Water Valve, which discharges the exact quantity of water with each batch by only one pressure of the lever and is attachable to any mixer. It is a small valve not larger than a quart measure but it is positive, accurate and perfect. Write for Catalog 25 and Agency Proposition BADGER CONCRETE MIXER & MACHINERY COMPANY, Majestic Building, Milwaukee Wis. The Concrete Highway ■^^■i""" is the ^^■■^™" Highway of the Future The road officer who makes a stand for concrete highways, and gets what he stands for, is sure of two things: — the best possible road at the right price — and freedom from patent litigation — essential in the building of concrete highways in good cement. /-"Chicago AA" has stood the test of time and is speci- fied by engineers and architects in work of greatest importance, and involving the expenditure of millions of dollars. ** Chicago AA" is made in one mill and from one quarry only. This ac- counts for its uniformity in strength and color, and is responsible for the well known saying regarding "Chicago AA" — "Every Sack the Same." Tell us your road problem — possibly we may be able to assist you. Our suggestions will be offered free. Chicago Portland Cement Co. 30 No. La Salle Street, Chicago TWO GREAT PAVING MIXERS The Grand and the Hartwick Continuous Mixers are ideal for paving construction, sidewalks, curbs, culverts and general highway work. The Grand has the best proportioning and feeding device to be found on any mixer. The Hartwick has a double trough, meaning thorough mixing and large output. Read what one paving firm writes : General Contractors Terre Haute, Ind., Dec. 17th, 1912. "We have been using the HARTWICK mixer for over two years with great satis- faction. Our purchase in October of our third machine is a pretty good evidence of our regard for the HARTWICK. For the kind of work in which we have been using it — concrete sidewalks and curbing — where it is necessary to do a large amount of work over considerable terri- tory, we do not know of a better mixer." — Foulkes Contracting Co. These mixers are made in sizes to fit a variety of requirements. If you need a mixer on high- way work, get our catalogs before buying. Hall-Holmes Mfg. Co. 502 Oak St.. Jackson, Mich. Concrete Road, Wayne County, New York The Highway of the Future The building of a country road to stand the strain of heavy traffic, calls for a concrete road, because it is economical and permanent. There is a difference between value and price. In purchasing cement, as in other things , the value should have first consideration. "Atlas" is. "The standard by which all other makes are. measured." THE ATLAS »-^"tland CEMENT CO. 30 BROAD STREET, NEW YORK Corn Excti. Bldg. Chicago, 111. Morris Bldg. Philadelphia, Pa. Plymouth Bldg., Minneapolis. Minn. ■I illlllllll ATLAS llltlllH^^^ EUREKA ROAD MAKER The Eureka's remarkable increase in sales and popularity are striking exam- ples of the one Continuous Mixer that has reached the top by sheer force of merit. Every purchaser is assured of guaranteed service and satisfaction. ASK FOR CATALOG EXCLUSIVE MAKERS: Eureka Machine Co. 75 Handy Street Lansing, Mich., U. S. A. United States Distributing Points Atlanta Dallas Fort Wayne Cedar Rapids Dayton Kansas City Chicago Detroit New York City Cincinnati Indianapolis Milwaukee Omaha Peoria Pittsburg Salt Lake City Minneapolis No. 15 Chain Belt Street Paver operated by one is absolutely a one man mixer in that all levers for operating the entire mixer are on one side. TRACTION — full reverse differential with speed about one mile per hour either direction. Traction controlled by friction clutch and is independent of drum drive. Mixer will climb 15% grade. POWER LOADER — open end, direct loading from ground level. Capacity of machine 60 to 75 batches per hour. DISTRIBUTING BOOM — works automatically and dumps at any point along the boom. Bucket is self closed when under discharge chute. Speed of boom bucket 110 feet per minute. The boom may be swung at 180 degrees or at right angles to mixer on either side of roadway. STEEL ROLLER CHAIN BELT DRIVE THROUGHOUT. Practically all castings used are of Refined Crucible Ste«l. If you are going to be in the market for a Street Paver Mr. Contractor we believe it will pay you to investigate the Chain Belt. CHAIN BELT COMPANY, Milwaukee REPRESENTATIVES IN 40 CITIES IS TIME MONEY TO YOU? Don't Lose Money Tying Up the Job for Weeks When Your Concrete Mixer Breaks Down. The Drive Gear of the "MC" Rail Track Concrete Mixer is composed of five interchangeable parts, made of the very best materials, but if a tooth should should break, one of the segments can be replaced in a few minutes without disturbing any other part of the machine. Just figure the saving in time and money. This is only one of the many advantages of <^ MC Rail Track Concrete Mixers They will do " Most Mixing, Least Fixing." The mix is absolutely perfect (never varies). They contain every known improvement and are posi- tively the "last word" in concrete mixers. The smoothest running mixers ever built. Our new'catalog'will be of wonderful help to you in buyingf f^af mixer; it's yours for the asking. Write today. Marsh-Capron Mfg. Co. Main Office— 489 Old Colony Building Marsh-Capron Rail Track Mixei Side LoadenGrounded ith Chicago SEP 11 Klf