Prediction of Dynamic Modulus of Asphalt Concrete Using Two-Dimensional and Three-Dimensional Discrete Element Modeling Approach

Abstract

The objective of this study is to predict the asphalt mixture dynamic modulus using both two-dimensional (2D) and three-dimensional (3D) discrete element models (DEM) generated using the X-ray computed tomography images. An experimental program was developed with a uniaxial compression test to measure the dynamic modulus of asphalt mastic and asphalt mixtures at different temperatures and loading frequencies. In the DEM simulation, the mastic properties and aggregate elastic modulus were used as input parameters. The strain response of the asphalt mastic and mixture models under a compressive load was monitored, and the dynamic modulus was computed. The mixture properties were obtained using images of aggregate, mastic, and air voids from the X-ray CT. The experimental measurements of dynamic modulus were employed to compare with the 2D and 3D predictions. It was found that the 3D discrete element models were able to predict the mixture modulus across a range of temperatures and loading frequencies. The 3D DEM models prediction is much better than that of the 2D DEM models.