This paper dealt with a laboratory study on the effect of the polishing process on the road aggregate microtexture. The polishing action was simulated by the projection of a water and fine abrasive mix under pressure. Evolution of the aggregate microtexture with the polishing time was assessed by profile analyses and Scanning Electron Microscope (SEM) observations. The profile analyses were based on a method developed at LCPC for characterizing the asperity shape end relief. The SEM observations were done at different magnification levels. Results from the profile analyses showed that polishing involves two microtexture scales: the “roughness” scale, composed of few ten microns asperities, and the “undulation” scale, composed of few hundred microns asperities. Evolutions of the asperity shape and relief at these two scales depended on the rock nature. SEM observations supported these results and gave a better insight into the evolution of the mineral surfaces, related to the rock properties.
