Concrete Roads
and Their Construction

30 CONCRETE ROADS The aggregate used was composed of equal proportions of granite broken to sizes H in., 1 in., in. and I in. free from dirt and dust ; the sand was washed River Dart sand. Cement was to the British Standard Specification. Frequent tests for voids were made, as a result of which the proportion of material worked out at about 4| to 1. The mixture was turned three times dry and three times wet, care being taken that only sufficient water was added to bring the whole to a plastic consistency. The centre of the road for a width of 12 ft. was 6 in. in thickness, the remaining 2 ft. on each side being 10 ins. The reinforcement was placed 21 in. from the bed. Very little ramming was done, the material being carefully deposited approximately to required levels and floated with a Fig. 20.—Road between Totnes and Paignton. long wooden template run on screeds of wood. No joints were provided for longitudinal expansion. Over a week’s frost was experienced whilst the work was in hand, which necessitated a stoppage, the section completed being covered with a layer of sand over which bags were placed. Care was taken to leave the edge of the work stepped, rough, and doubly reinforced, so as to form a good key when a recommence- ment was made. No injury was done by the frost, nor is the junction noticeable. Five weeks after completion the surface was sprayed with refined tar and the road opened to traffic.