Observations on aspects of skid-rsistance of greywacke aggregate

The paper outlines recent investigations concerning the Polished Stone Value (PSV) test method. Although the research is limited to greywacke aggregate from Northern Ireland the results indicate that the standard PSV test may not adequately predict the ultimate level of skid-resistance reached by the aggregates assessed. Extending the duration of polishing further decreases skid-resistance. Modifying the apparatus to simulate cornering situations using angled polishing produced significant reductions in skid-resistance. It was also shown that results may alter when the aggregate size is decreased. The paper concludes that further research is necessary in order to predict the in-service performance of aggregates in the laboratory.