Laboratory Assessment of Skid Resistance for High RAP Content Warm Mixed Asphalt

This paper presents results of laboratory skid resistance testing for three asphalt mixtures containing 0, 50, and 100% reclaimed asphalt pavement (RAP) to evaluate the effects of RAP on surface skid resistance. The mixtures were successfully produced in the laboratory at 116 C with the aid of warm mix additives. A novel technique for fabricating 508 by 508 mm panels for laboratory skid resistance testing is also presented. Skid resistance testing was performed with a dynamic friction tester (DFTester) in conjunction with a circular texture meter (CTMeter). Results were used to calculate international friction index (IFI) values for the three mixtures. IFI results were used to estimate locked wheel skid trailer skid number (SN) values for the mixtures with a correlation from published literature. Based on this limited laboratory assessment, the anticipated skid resistance immediately post construction is not believed to be problematic for warm mixed surface mixtures containing elevated RAP contents.