Asphalt-Mixture Force Chains Length Distribution and Skeleton Composition Investigation Based on Computational Granular Mechanics

Abstract

In asphalt mixtures, external loading transfer paths can be deemed as force chains. The force chains difference can be used to evaluate skeleton structure. In this study, various asphalt mixture virtual specimens were established via discrete-element method (DEM) to investigate force chains length distribution and skeleton composition. Results indicate that, although dense-graded asphalt mixtures (AC) generate a large number of force chains compared with stone mastic asphalt (SMA) and open-graded asphalt friction course (OGFC), most of them are shorter length force chains that are not conductive to transfer external loading. When asphalt mixtures were penetrated to the same depth, asphalt mixtures with smaller nominal maximum aggregate size (NMAS) need more force chains to transfer external loading. In asphalt mixtures, the increase of NMAS can help to form longer length force chains. The passing percentage of 2.36 mm (P2.36) increase can lead to form more short length force chains. In asphalt mixtures, less than 50% quantity aggregates participate in skeleton composition. The aggregates within 2.36 mm participate in skeleton composition for AC16. Skeleton composition difference between AC and skeleton type asphalt mixtures is mainly affected by P2.36.