Show DEVELOPMENT OF CONCRETE ROAD By Fred R. Paper read at the annual meeting of the Indiana Engineering The city of cannot claim to have a large amount of concrete but it laid some of the earliest street pavements of this Our first roadway was laid in and now has nearly 14 years of life and usefulness to its and is still continuing its service without having cost one cent for In truth this was a small and owing to the excellent character of its macadam our city has been backward in constructing permanent but nevertheless this first concrete roadway has abundantly justified its so that for the last eight or ten years the amount has been added to by a small amount There was nothing especially remarkable about the construction of this first except that extreme care was used in all the particularly the minor and I wish to state here that we endeavor in all our cement work to watch carefully the small remembering the isi made up of but perfection is no Perfection has not been reached far from it but at first you don't try The natural soil under the first pavement is so that no sub-base was The concrete was proportioned deposited five inches thick after with a top surface one inch proportioned 1 to It was cut into blocks about five feet square and the surface pitted with an ordinary lug In the subsequent various have been The principal variations consist in the material for thickness of with and a top thickness of the size of thickness of joints and material used One roadway was cut in blocks eight to ten feet another thirty to forty feet all joints between the both cross and are one inch wide and filled with paving The defect of this method consists in the chipping of the concrete edges at these principally the longitudinal Our experience seems to show the blocks should be as large as possible in order to reduce the number of and that the joints should be as thin as can be On the other we find that blocks ten to fifteen feet square are about as large as can be made without developing temperature cracks in our These apparently do not injure the beyond detracting from its as cracks that have existed for years show no and the pavement up to and over the cracks is as solid as Possibly there have been but I have no knowledge of to ascertain what size of blocks are safe in different or places with different ranges of Corrugating or grooving the surface is also objectionable for the same reasons as are the joints the edges of the grooves afford an opportunity for the concrete to chip and spall off by the action of horses' Also the grooves catch and collect the interfering with the cleanliness of the pavement and rendering it more difficult to Possibly the corrugations afford slightly better foothold for but I think even here the advantage is We obtain a very good surface by using one part cement to two parts coarse screened through a i trowel down to remove all air and with a cork or wood giving a rough gritty on which horses can maintain their footing as securely as on a cement-filled or or wooden block pavement when For ordinary traffic pavement we find excellent results are secured by the use of five of and a top surface one and a half inches mixed 1 to For automobile travel nothing could be more Of it is trite and unnecessary to say that care must be used in selecting good aggregate proportioning properly to reduce voids to a and securing good workmanship in all the of placing and finishing the I am a firm believer in for as well as for most other concrete Place this concrete on a well prepared using suitable straight edges and templates cut to the required crown of the tamp or jostle make a compact leaving the surface rought to provide attachment for the top cut joints through the concrete every ten to fifteen and fill with Before the concrete begins to place thereon the top composed of 1 part cement to 2 parts coarse trowel md cutting joints directly over in the using a small radius to leave as thin a point as and finally finish by means of a leaving the surface as rough as This gives a roadway very suitable for our For heavier six inches of concrete and two inch top surface is We have also had good results by making the pavements homogenous that without the top Make the concrete somewhat richer in cement and quite Tamp until free mortar flushes to the then finish with trowel and For this purpose the concrete should be free from large as with a large stone at the if one end becomes worn a large leverage is afforded to tear the remainder of the stone from the As remarked the disadvantage of concrete is its lack of whereby exposed edges of joints and corrugations are prone to chip and wear For this reason joints ought to be reduced to a an longitudinal joints should be eliminated wherever Another defect urged against concrete is its lack of This contention does not seem to be well as concrete is not the only Brick on concrete foundation and with a cement filler seems to be about as unyielding and non-elastic as any roadway could Of for horses some elasticity is but in view of the increasing numbers of motor vehicles this quality is not so essential to so many users as The present laws of the state of passed avowedly in the interests of the asphalt paving ought to bring about the increased use of concrete For plans must be made for a foundation suitable for any kind of modern city which foundation naturally will be Then the specifications must and bids be received for four different paving materials to go on top of this concrete After receipt of bids the property owners have the right to determine which one of the four shall be and since cheapness usually appeals to the average property asphalt often wins to because with the same foundation specified for each the top surface of asphalt can be put on at less cost than Here is the chance for concrete Put down a foundation suitable for any kind of viz five or six inches in depth of placed and jointed as above then before this concrete begins to place thereon the material consisting of the wearing surface 12 or 2 inches mixed with one pan cement and two parts as and you will have a Pavement that can compete with any other i and will cost less in and will give a sanitary and will come as near to satisfying w as you can ever hope to that exacting |