Trrl Lr 1082

In 1972 a full-scale experiment was begun on A33 Winchester by pass to compare the road performance of rolled asphalt wearing-cources with the results of three laboratory design procedures. eight wearing-cources were investigated, each containing a different sand fine aggregate. The results after seven years of service show that, although the properties of rolled asphalt are tolerant of variations in binder content, good performances can be obtained by designing the mix using laboratory mechanical tests. Marshall tests amd wheel tracking tests on complete rolled asphalt mixtures gave the best overall assessment of an optimum binder content, together with a direct measure of the resistance to deformation. These tests generally gave a better assessment of the optimum binder content than did the design method specified in Section 3 of BS 594:1973 using the mortar only