Investigation of the effect of particle composition on its distribution homogeneity in aggregate blend using discrete element method

Abstract

The homogeneity of aggregate blend has a significant influence on the performance of asphalt mixture. The composition of aggregate blend, including the size combination and the mass ratio between each size particles (MRESP), is an important factor affecting the homogeneity. This study investigated the influence of the size combination and MRESP on the distribution homogeneity of particles in aggregate blend using discrete element method (DEM). An indicator quantifying the distribution homogeneity was established according to the coefficient of variation (CV) for particle number. Two-size, three-size, and four-size aggregate blends with various compositions were designed. Laboratory tests show the DEM simulation is feasible. The particle distribution homogeneity in various blends was analyzed. The results showed the distribution homogeneity of each size particles in a blend is closely related to their mass fraction. The higher the mass fraction of the particles, the more homogeneous the distribution of them. The MRESP has no significant influence on the homogeneity of the blend composed of only coarse aggregates. However, the homogeneity of the blend composed of coarse and fine aggregates improves gradually with the increase of the mass fraction of fine aggregates. The smaller the maximum particle size in a blend, the better the homogeneity. It is suggested that the mass fraction of fine aggregates should be between 33% and 50% for achieving good homogeneity of aggregate blends. The research results can provide a reference for gradation design of asphalt mixture.