Evaluation of skid resistance of exposed aggregate concrete pavement in the initial exploitation period

Abstract

The paper presents the evaluation of skid resistance of pavements in their early life on the basis of macrotexture and microtexture changes determined with the Circular Texture Meter (CTM) and the Dynamic Friction Tester (DFT). Tests were performed on two test pavement sections made from exposed aggregate concrete on S8 expressway located in Poland. The relevant parameters, namely the Mean Profile Depth MPD and the friction coefficient DFT 20 were measured after two and six weeks from pavement construction and then after three and sixteen months of traffic loads. No changes to the macrotexture were observed in these periods. However, significant changes were observed in the microtexture. The lowest values of DFT 20 were determined two weeks from paving, indicating the effect of increased slipperiness just after placement. This lower initial friction coefficient DFT 20 can be attributed to the presence of curing agent residue. Such residues are gradually removed from the pavement surface by weathering and trafficking and then the value of DFT 20 stabilizes and stays constant at a certain level. The coefficient of friction decreased by ca. 20% in the period between the third and the sixteenth month of trafficking. Finally, the results of evaluation were compared with the classification system developed in the U.S., based on the International Friction Index IFI .