Modern increases in traffic density and vehicle performance require an increasingly demanding specification for road surfaces in order to maintain an adequate resistance to skidding. The use of resin-bound surfacing systems, employing refractory-grade calcined bauxite aggregate of about 3mm in size, has given a significant reduction in accidents at a number of dangerous road sites. This report gives a summary of existing information relating to the performance of different aggregates in resin-bound surfacings, and relates this performance to the results of laboratory testing. Further work, including the development of special tests, needs to be carried out before a firm specification for suitable aggregates can be drawn up, but the report includes such conclusions as can be drawn at this stage. The most important findings were: 1. the best aggregates for resin- bound surfacings were certain calcined bauxites and similar corundum-rich materials. No other aggregates were entirely satisfactory, but of the materials studied, two irish basalts gave the best performance and two glassy materials gave the worst. 2. good performance in resin-bound surfacings was associated with materials combining a minimum polished-stone value of 70 with a maximum aggregate abrasion value of 5. (Author/publisher)
Abstract