Micromechanical Discrete Element Modeling of Asphalt Mixture Shear Fatigue Performance

Abstract

This study aims to investigate the shear fatigue performance of asphalt mixture and factors influencing performance using a three-dimensional (3D) discrete element method (DEM) incorporated with the Burgers model. The repeated uniaxial penetration test (RUPT), which is a shear fatigue test method for asphalt mixtures, was succinctly described. A 3D micromechanical model for the prediction of asphalt mixture’s shear fatigue life was built using particle flow code in three dimensions. The influence of aggregate size, temperature, binder content, air void, and loading/penetration frequency on the shear fatigue life were simulated based on this model. Simulation results were validated by performing a laboratory RUPT. Research results revealed that an asphalt mixture’s shear fatigue life could be simulated well using a 3D DEM. Aggregate size, temperature, binder content, air void, and loading frequency considerably affected the asphalt mixture’s shear fatigue life. Shear fatigue life increased with the nominal maximum aggregate size or loading frequency and decreased with the increasing temperature or air void. At 60°C, shear fatigue life was the largest with optimal binder content.