New laboratory procedures for assessing polishing and skid resistance - review

The Highways Agency’s Wehner/Schulze (W/S) machine, the first in the UK, has shown potential for use in determining the long-term skid resistance of aggregates, asphalt mixtures and cores. This report describes the first stages of a project to evaluate its use as a procedure for assessing the polishing resistance and skid resistance of aggregate used the UK. Technical exchange visits to the national laboratories in France (LCPC) and Germany (BASt) have allowed discussion with researchers carrying out evaluation programmes of their own W/S machines. Relevant literature is briefly reviewed. The main goal of the overall project is to evaluate the machine’s use as a tool for assessing the polishing resistance of road aggregate. In this way, the most interesting experiments described in the literature are those comparisons with the current standard method, the polished stone value test. Generally, the research described confirms the need to experiment further, using the machine with UK-specific materials. (A)