Abstract
A discrete element method (DEM) has widely been used to simulate asphalt mixture characteristics, and DEM models can consider the effect of aggregate gradation and interaction between particles. However, proper selection of model parameters is crucial to obtain convincing results from DEM-based simulations. This paper presents a method to appropriately determine the mechanical parameters to be used in DEM-based simulation of asphalt concrete mixture. Splitting test specimens are prepared by using asphalt mixture, and the splitting test results are compared with simulation results from two-dimensional (2D) DEM and three-dimensional (3D) DEM. Basing on the DEM results, the effects of contact model parameters on the simulation results are analyzed. The slope of the load-displacement curve at the beginning stage is mainly affected by the stiffness parameters, and the peak load is mainly determined by using the value of the bond strength. The laboratory splitting test of AC-20 and AC-13 specimens were performed at different temperatures, namely, −10°C, 0°C, 10°C, and 20°C, and the load-displacement relationships were plotted. According to the real load-displacement curve’s slope at the beginning stage and peak load applied, the range of DEM bond model parameters is determined. On the basis of DEM results of the splitting test, the relationships between simulation load-displacement curve’s characteristics and bond model parameters are fitted. The values of the parameters of the DEM contact bond model at different temperatures are obtained depending on the actual load-displacement curve’s initial slope and peak load. Lastly the DEM and laboratory test results are compared, which illustrates that the parallel bond model can well simulate the behavior of asphalt mixture.
Highlights
Asphalt mixture is a composite material comprised of graded aggregate, filler, asphalt, and air voids
In 1992, Rothenburg and Bathurst [6] established a discrete element method (DEM) model of asphalt mixture using a series of plane particles and the simulation results showed that 60% of the unconfined compressive strength was contributed by the bonding between particles and the remaining 40% was provided by the Advances in Civil Engineering friction action between particles
In 2005, You and Buttlar analyzed the dynamic modulus of asphalt mixture basing on a two-dimensional DEM. e results showed that simulation results for relatively thick asphalt mixture were in good agreement with test results [8]
Summary
Asphalt mixture is a composite material comprised of graded aggregate, filler, asphalt, and air voids. Hossian et al [11] used a two-dimensional discrete element method to study the influence of the shape of aggregate on the mechanical properties of gravel mixtures. Aggregate sphericity and angularity, air-void distribution, aggregate orientation, aggregate contact points, and aggregate distribution were analyzed based on the discrete element model. In the authors’ previous study, the splitting test was simulated basing on DEM and the influences of the bond model parameters on simulation results were analyzed [27]. Is study proposes a method to determine the parameters of a DEM-based contact bond model.
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