Skid Resistance Predictive Models for Asphaltic Concrete Surface Courses

Skid resistance performance models for dense and open graded asphaltic concrete surface courses are presented. Previous studies for dense graded mixes and high traffic volumes resulted in a predictive linear model for theskid number (SN) at 100 km/h (60 mph) (SN 1 0 0 ) in terms of known aggregate and mix parameters and available traffic data. However, the SN 1 0 0 does approach a constant level requiring a rational function to describe traffic influences. Further work has confirmed the overall importance of mix designs in achieving desired skid resistance with accumulated traffic influences, particularly in preventing coarse aggregate immersion due to traffic compaction. High stability mixes (all steel slag, blast furnace slag, or traprock, for instance) have proven most suitable, and coarse aggregate factors such as polished stone value and aggregate abrasion value are of secondary importance once adequate levels are provided. Using a wider range of test sections, improved predictive models have been developed for various traffic volumes and surface types. Full details on model development are given.