Mechanical Response and Damage Behavior Analysis of Asphalt Pavements Using a 3D Coupled Thermomechanical Multiscale Modeling Method

Abstract

Asphalt concrete (AC) exhibits complex damage behavior under the combined effects of environmental factors and loads. Phenomenological models may encounter difficulty in deeply explaining its damage evolution mechanisms. To solve this issue, this study developed a multiscale method that establishes a two-way coupling between the macroscopic and mesoscopic finite element (FE) models of AC. Thermal and mechanical properties at both scales as well as the damage behavior at the mesoscale were simultaneously considered. A representative volume element (RVE) of AC was developed based on computed tomography slices and digital image processing methods. An automatic insertion method for 3D cohesive elements suitable for complex structural FE models was proposed, and an RVE model with cohesive elements (RVE-coh) was established. Transient thermal stress fields of asphalt pavement were solved based on real climatic data and sequential coupling computation. A localization method was proposed for determining mesomechanical responses based on 3D shape function interpolation. The multiscale FE method was applied to analyzing the process of reflective crack initiation. The results showed that this method effectively considers the heterogeneous characteristics of AC and the combined effects of temperature field and wheel load. It provides in-depth insights into the mesomechanical responses and the evolution process of damage within the pavement structure.