3D identification and characterization of force chains in asphalt concrete based on continuum mesomechanics

Abstract

Force chains occurring within particle assemblies have been extensively investigated based on granular mechanics; however, research on their identification and characterization in asphalt concrete, where coarse aggregates are dispersed in a viscoelastic asphalt mortar matrix, has been still very limited due to the lack of identifying criteria. A three-dimensional (3D) finite element (FE) simulation-based method was proposed to identify and characterize force chains of asphalt concrete from a continuum mesomechanics perspective. Stress concentration regions within the asphalt mortar matrix were treated as the main load-transfer regions (MLRs) between coarse aggregates. The MLRs were identified by a local detection method that inspects whether an asphalt mortar element is highly stressed in its local region. The load-transfer aggregates were then determined if their effective contact areas, i.e., the asphalt mortar elements sharing the nodes with aggregate elements, were found simultaneously containing an MLR, thereby enabling force chain identification. The compressive force chains in several 3D asphalt concrete mesostructures were determined and quantitatively characterized. The results indicate that the proposed method can effectively identify the force chains in asphalt concrete and their characteristics can be used to quantitatively evaluate the aggregate skeleton.