Discrete element modelling of mechanical response of crumb rubber-modified asphalt pavements under traffic loads

This study aims to predict the mechanical response of crumb rubber-modified (CRM) asphalt pavements under traffic loads using three-dimensional (3D) discrete element method (DEM). First, irregular-shaped aggregates were generated in Python language, and discrete element models of six different asphalt layers, which considered the temperature gradient and fatigue damage, were established using 3D DEM. Then, model parameters were obtained through the uniaxial creep test for asphalt mastics at different temperatures. The fatigue damage was implemented by introducing a damage factor into the Burgers model. Finally, three mechanical response parameters (namely, permanent deformation, shear stress and transverse strain) of the six asphalt layers under traffic loads were analysed and compared. Results show that the mechanical response of CRM asphalt layers under traffic loads is significantly influenced by number of repeated loads, temperature, and asphalt layer materials. The shear stress and transverse strain at the wheel centre vary along the depth of asphalt layers, and the middle layer is the principal area of shear stresses in asphalt pavements.