The paper dealt with the use of geometric parameters to measure the degree of polishing of road surface aggregates. Microtexture asperities were characterized by two angular parameters related to their shape and relief. The polishing action was simulated in laboratory by means of a French device, which was developed as an alternative to the British Accelerated Polishing Test. Three road stones were studied. Friction and microtexture measurements were carried out at different polishing stages. The friction was measured by means of the Skid Resistance Tester. The microtexture profiles were measured by means of a very high-resolution laser sensor, providing profiles with a 1 μm sampling length. The variations of the friction could be satisfactory explained by the evolutions of the microtexture parameters with the polishing time. Two microtexture scales were defined to take into account the roughening effect, which occurred on polymineral stones in the beginning of the polishing process. Interpretations from the profile analyses of the effect of polishing on the characteristics of microtexture asperities such as the size, shape and density were corroborated with the polishing mechanisms based on petrography examinations.
Assessment of the Polishing of the Aggregate Microtexture by Means of Geometric Parameters