Packing structure of porous asphalt mixture (PAM)

Abstract

The main research objectives are to have better understanding on the packing structure of porous asphalt mixture (PAM), and the influence of aggregate gradation and shape properties on the packing structure of PAM. A series of laboratory measurements and discrete element method (DEM) simulation were applied to assess the properties of PAM. Four packing parameters were developed from DEM model, namely porosity, coordination number, proportion of effective particles, and average of contact force. The results showed that proportion of 4.75 – 2.36mm fraction is critical on the packing structure of PAM, thereby the proportion of this fraction should be controlled. The recommended proportion of 4.75 – 2.36mm fractions is found to be 5-22%. Furthermore, aggregate shape properties showed important influence on aggregate packing structure and properties of PAM whereby aggregate shape properties determine the degree of stone-on-stone interlocking between particles. Furthermore, DEM simulation is deemed feasible to simulate packing structure of PAM.