Concrete Roads
and Their Construction

108 CONCRETE ROADS Reporting on the test Mr. Aughtie said it had conclusively shown that there had been absolutely no wear on the surface, and to all appearances it was as sound as on the day on which it had been laid. A number of transverse cracks, however, had appeared in the plain concrete road and at the junction of the reinforced road, but very few had shown themselves in the latter. Taking the reinforced sections as a whole, the cracks were of a very minor nature and the structure gave evidence of durability. New South Head Road, Sydney.—Some time ago the Woollahra Council, Sydney, experimented with a section of the New South Head Road, near Mona Road, Darling Point. There is a founda- tion oi a depth of 6 in., consisting of concrete made in the following proportions :—-8 cu. ft. of l|-in. blue metal, 8 ft. of |-in. metal, or “ shivers,” 10 ft. of blue metal screenings, and 4 cu. ft. of cement. Over this layer of concrete is laid the reinforcement. Above this is the wearing course, which consists of a rich concrete mixture of two parts of blue metal screenings to one of cement. The length of road constructed was 160 ft., with expansion joints 20 ft. apart. Canada The Toronto-Hamilton Highway.—This is one of the most interest- ing examples of concrete road construction in Canada, and is thirty-five miles in length. The former Engineer of the Toronto- Hamilton Highway Commission, Mr. A. E. Wynn, has recently stated that this road represents the best and most modern practice in road building. For this reason we give some brief particulars of its construction, together with illustrations. The road is a link of the Provincial Government’s scheme for a system of main highways connecting the towns, and it carries more traffic than any other road in Canada. Its construction was undertaken in the autumn of 1911. The specifications adopted very closely followed those of Wayne County, Michigan, which is the pioneer district for concrete roads. All work was done by day labour under the supervision of the Commission’s engineers. The pavement itself had a standard width of 18 ft., with shoulders