Generalized Maxwell Viscoelastic Contact Model-Based Discrete Element Method for Characterizing Low-Temperature Properties of Asphalt Concrete

A universal asphalt concrete discrete element method (DEM) model was established in this paper. Coarse aggregates consisting of balls bonded by elastic contact models were simulated using irregular particles. Asphalt mastic consisting of balls bonded by a generalized Maxwell viscoelastic contact model held coarse aggregates together. The generalized Maxwell viscoelastic contact model was developed based on a finite difference scheme using Visual Studio 2005. The relationship between microscale model input and macroscale properties of asphalt mastics and coarse aggregates was derived to calibrate contact parameters of the proposed DEM model. Dynamic modulus tests, static creep tests, bending tests at low temperature, and the corresponding DEM simulations were implemented to contrast the simulation effect of the proposed DEM model and the existing DEM model. Simulation results show that the proposed DEM model exhibits an improved accuracy using a universal mathematical structure. The averaged and maximum relative errors of different property indexes are all less than 5 and 8%, demonstrating the advantage of the proposed DEM model in accurately and comprehensively characterizing low-temperature properties of asphalt concrete. The proposed DEM asphalt concrete model provides a new avenue for studying pavement properties and mechanical mechanisms of asphalt concrete at microscale.