| 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 v 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 dantly 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 is made up of but perfection is no Perfection has not been reached far from it but at first you don't try natural soil under the first pavement is so that no sub-base was The concrete was 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 with an ordinary lug In the subsequent various plans 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 11 the beyond detracting from its as cracks that have existed tor 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 ot Corrugating or grooving the surface is also objectionable for the same reasons as are the 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 4 trowel down to remove all air and with a cork or wood giving a rough gritty on which horses can maintain their 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 inches 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 operations 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 street tamp or jostle to make a compact leaving the surface rought to provide attach- ment 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 cutting joints directly over nose 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 suitable for our a roadway very For heavier six inches of concrete and two inch top surface is |
