Directional Characteristics of Dense-Graded Asphalt Pavement Skid Resistance Deterioration along a Horizontal Curve

Directional variations in pavement skid resistance deterioration at a given point along a horizontal curve is not well understood. Moreover, the pattern of these variations of directional skid resistance at different points along a horizontal pavement curve is also not well understood. A field experimental program was undertaken in this research to study these two aspects of the directional characteristics of skid resistance deterioration along a pavement curve under the polishing action of traffic. The British pendulum test (BPT) was used to measure directional skid resistance at selected points along the wheel paths of two in-service pavement curves. It was found that the skid resistance at any given point on the curve varied with the test direction, and the variation pattern of directional skid resistance changed from point to point along the curve. The variation pattern of directional resistance could be explained by the directions of tire forces acting on the pavement. Laser scanned images were also taken at all the test points. A directional wear index (DWI) was defined to characterize the directional characteristics of pavement surface texture. A highly significant relationship with coefficient multiple determination R 2 of 0.92 was found between the DWI and a measure of directional skid resistance. It provides a potentially useful means to estimate the degree of pavement polishing and the corresponding directional skid resistance at a given point based on laser scanned images of pavement texture.