Effect of morphology characteristics on the polishing resistance of coarse aggregates on asphalt pavement

•88# calcined bauxite shows excellent mechanical properties as a kind of aggregate.•Macro morphology characteristic parameters of coarse aggregates satisfy normal distribution.•The fractal dimension and Rq have strong correlation with PSV of coarse aggregates. Skid resistance performance of asphalt pavement is an important factor affecting the traffic safety. The long-term skid resistance performance of asphalt pavement depends on abrasion and polish resistance of aggregates. However, the mechanical properties and surface morphological characteristics of aggregates not only affect the road bearing capacity, but also impact the long-term abrasion and polish resistance of asphalt pavement. In this study, the mechanical properties of limestone, basalt, granite and 88 # calcined bauxite were investigated. The macro morphology characteristic parameters (MACP) of coarse aggregates were obtained by Image Pro Plus (IPP) software analysis with strong applicability, and the distribution models and characteristics were further analyzed. In order to present quantitatively the dynamic change process of the macro and micro morphology characteristics of coarse aggregates with the polished stone value (PSV) during the polishing process, a long-term polishing test was carried out on the coarse aggregates. The MACP and micro morphology characteristic parameters (MICP) of coarse aggregates were obtained by the IPP analysis and three-dimensional laser microscope. The grey relation entropy analysis method was used to analyze the correlation degree between morphological characteristic parameters and PSV. The results show that the contents of corundum and mullite in 88 # calcined bauxite are 85.2% and 14.8% severally. Corundum and mullite have the highest Mohs hardness, 9 and 6 respectively. The IPP analysis is suitable for quickly obtaining the MACP of coarse aggregates, and the MACP distribution of four kinds of coarse aggregates satisfies well normal distribution. In addition, in the process of PSV attenuation, the grey entropy correlation coefficients between PSV and fractal dimension, Rq are the highest, 0.9037 and 0.8882 respectively. The fractal dimension of MACP and Rq of MICP are selected as the main various indexes. Meanwhile, the average correlation coefficients of fractal dimension, Rq and PSV are 0.9589 and 0.9809 separately. Therefore, the fractal dimension and Rq are proposed to evaluate the long-term polishing resistance performance of coarse aggregates, and to p