Evaluation and Measurement of Pavement Skid Resistance

摘要

The International Friction Index (IFI) consists of a Friction Number (F60) and a Speed Constant (Sp). F60 indicates friction at a slip speed of 60 km/h. On the other hand, Sp indicates the speed dependency of the friction coefficient and is influenced by the macrotexture of the pavement. This paper describes the development of two testers which can measure the skid resistance and the macrotexture of pavement surfaces, and their application for estimating the IFI. The Dynamic Friction Tester (DF Tester) was developed for measuring the coefficient of friction and its speed dependency of the pavement surfaces. The Tester is a disc-rotating type which measures the friction forces between road surfaces and three rubber sliders attached to the disc. The DF Tester was standardized as ASTM Standard E 1911-98. Another device developed is the Circular Texture Meter (CT Meter) which measures the macrotexture profiles on a circular track of 142 mm radius using a laser displacement sensor. The CT Meter is a portable device and is able to measure on the same circumference where the DF Tester measures the coefficient of friction. The CT Meter was standardized as ASTM Standard E 2157-01 in 2001. It has proven that the developed testers were successively used to predict the two components of IFI.