Micromechanical Analysis of Asphalt-Mixture Shear Strength Using the Three-Dimensional Discrete Element Method

Abstract

This study investigated the shear strength of asphalt mixtures and its influence factors by using a three-dimensional (3D) discrete-element method (DEM). The uniaxial penetration test, a shear strength test method for asphalt mixtures, was briefly introduced. A 3D micromechanical model for predicting asphalt mixture shear strength was established by using Particle Flow Code in Three Dimensions. The effects of aggregate size, temperature, asphalt content, and loading rate on asphalt mixture shear strength were simulated based on this model. Simulation results were verified via an actual uniaxial penetration test. The results showed that asphalt mixture shear strength could be effectively simulated based on 3D micromechanical DEM. Aggregate size, temperature, asphalt content, and loading rate significantly affected asphalt mixture shear strength. Shear strength increased with an increase in nominal maximum aggregate size (NMAS) or loading rate, decreased with an increase in temperature, and was the highest with the optimal asphalt content at 6°C.