Macro- and micro-texture evolution of road pavements and correlation with friction

This article features a field experiment conducted on existing road pavements to characterise macro- and micro-texture variations at actual road conditions and to substantiate links to friction values. Three-dimensional inspections of the wearing course surface of three asphalt mixes were performed during a short period of 9 months. Several statistical texture indicators, spectral analysis and photo-simulated images of surface height maps were employed to analyse macro/micro-texture evolution and to study the physical phenomena behind it. Fractal and non-fractal parameters, with a focus on Hurst exponent (H), were used in associating texture with friction. The results of texture evolution clearly state that changes in macro/micro-scales occur within full surface profile and not solely from the polishing phenomena of a small percentage of top surface topographies. It was demonstrated that H, as an indicator of full surface profile specification, could not be employed for road texture–friction studies at actual road conditions.