Influence of aggregate particles on mastic and air-voids in asphalt concrete

The main objective in this paper is to determine the effect of aggregate particles on internal structure in asphalt concrete. Binary images of real microstructures were obtained based on Otsu thresholding method with different annular regions and three-dimensional finite element models were reconstructed. Prony series inferred from Generalized Maxwell Model were used to describe the viscoelastic behavior of asphalt mastic, and then, using numerical simulations to investigate the effect of aggregate particles on stress and strain field in asphalt mastic at high temperature. In addition, Box-counting method calculated the fractal dimensions of aggregate particles to analyze the influences of aggregate shape on air-voids. Results indicate that the improved Otsu can effectively extract the microstructural characteristics of aggregate particles, enhancing the accuracy of numerical simulation and calculation; The proportion of coarse aggregates and corresponding sizes have an obvious impact on stress field in asphalt mastic, high-temperature damage is mainly caused by coarse aggregate particles; The major component of total strain in asphalt mastic is creep strain, and the creep strain increases with the increase of aggregate particle size; fractal dimensions of aggregate particles have significant effect on air-voids distribution. (C) 2015 Elsevier Ltd. All rights reserved.