GripTester measurements and texture-friction relationship

Abstract

The influence of test conditions such as test speed, pavement condition (wet or dry) and tire temperature on pavement friction measurements and texture-friction relationship was investigated. The skid resistance of an asphalt pavement section in Qatar was measured at test speeds of 35 and 50 km/h in dry and wet conditions, respectively, using a GripTester. The tire temperature was monitored using embedded small sensors. Close Range Photogrammetry (CRP) surface texture determination entailed using a camera for capturing pavement surface images, and analyzing the images with proprietary software. Both test conditions caused significant differences in grip numbers, but the average grip numbers fell within a narrow range (0.21–0.24). Among the texture parameters considered, only the peak material volume (Vmp) showed reasonable correlation (R = 0.61–0.78) with friction for both test conditions. The results suggest that the influence of test conditions on skid resistance decreases for smoothly polished pavement surfaces.