Pavement polishing—Development of a dedicated laboratory test and its correlation with road results

Skid-resistance of trafficked roads decreases due to polishing and can have a drastic consequence on the driver safety. There is a need to dispose of a laboratory test to forecast such variations on asphalt-mix specimens before the road construction. This paper is focused on the development of a polishing methodology using the so-called Wehner/Schulze machine. Three trafficked roads have been monitored since their construction to provide data on actual friction evolutions. Specimens are taken from the pavements just after the road construction and subjected to polishing tests. The comparison between laboratory evolution curves and road data shows that, after two years of traffic, the polishing procedure is relevant. Tests on aggregates show that the friction variation of the asphalt mix is controlled by the aggregates, once the binder layer is removed by the traffic. Analyses of surface profiles show that the aggregate friction-variation due to polishing action can be explained by a modification of the aggregate microtexture.