Fundamental study on the discontinuities and heterogeneities of asphalt concrete

The thermal properties of hot mix asphalt concrete are investigated. The microscopic model, TRUBAL, based Discrete Element Method (DEM) is modified by including asphalt cement binder to model asphalt concrete. The rheological analog of viscoelastic asphalt cement is represented by Bergers elements, a combination of springs and dashpots. Two Bergers elements were inserted in the modified TRUBAL program at each aggregate contact in shear and normal directions. The temperature dependence of viscous element was used to study the high temperature rutting of asphalt concrete. The input parameters for the Burgers elements at different temperatures were back-calculated from the master curves for asphalt cement. The input parameters for Burgers elements and other properties of asphalt and aggregate were used to simulate the mechanical behavior of HMA. Series of numerical simulations were conducted under different loading and environmental conditions to observe the macroscopic stress-strain behavior and microscopic movement of particles.