Impact of Aggregate Packing on Dynamic Modulus of Hot Mix Asphalt Mixtures Using Discrete Element Method

摘要

Aggregates are the major component of hot mix asphalt (HMA) mixtures. The properties ofaggregates and the way of aggregate packing have important influence on the performance ofHMA mixtures. Because the dynamic modulus is considered as the most important HMAproperty influencing the field fatigue and rutting performance of a flexible pavement and areused in the mechanistic-empirical pavement design guide for determining the stress-strainresponses of the pavements, a study of the impact of aggregate packing on dynamic moduluswill provide insight on the HMA mix design and the material performance evaluation. Thispaper studies the effect of aggregate size distribution and angularity distribution on dynamicmodulus using a 3D discrete element method (DEM). Angular particles are generated usingan image-based ball-clumping approach. These particles are assigned to the DEM dynamicmodulus specimen based on the angularity distributions of the actual experimental specimen.A 3D DEM dynamic modulus model is thus established and calibrated using experimentaldata. This calibrated model is further used to evaluate how the different aggregate packingdue to the change of the proportions of aggregate particles and the change of aggregateangularities can result in the change of dynamic modulus.