Predicting Dynamic Shear Modulus of Asphalt Mastics Using Discretized-Element Simulation and Reinforcement Mechanisms

Dynamic shear modulus of an asphalt mastic has a remarkable effect on the mechanical performance of an asphalt pavement, and particulate composite micromechanical models are proven to be suitable for the prediction of modulus of asphalt mastics. However, the prediction accuracy of the current micromechanical models decreases sharply at a high filler concentration and high temperature (or low frequency). This study aims to develop a modified micromechanical model that can be applied to predict modulus of asphalt mastics at a wide range of frequencies and filler concentrations. Dynamic shear rheometer (DSR) tests are performed using asphalt mastics with four filler concentrations, and three-dimensional discrete-element method (DEM) is implemented to validate the DSR tests and obtain additional master curves of asphalt mastics with different filler concentrations. The reinforcement mechanisms are introduced into the micromechanical models to predict the laboratory test results with an increase of the prediction accuracy. The numerical results show that the test data is repeated by the DEM simulation, which is believed to be a promising tool to present the rheological behavior of asphalt matrix and asphalt mastics. The modified micromechanical viscoelastic model can predict the dynamic shear modulus of asphalt mastics successfully at high filler concentration and low frequency.