Coupled thermo-mechanical modeling of reflective cracking in flexible pavements

This study presents a coupled thermo-mechanical finite element modeling to simulate the reflective cracking of flexible pavements. The method integrates principles from computational fracture mechanics, specifically focusing on the mixture-level fracture characteristics of bituminous materials, and links them with a structural-level model for the deformation and cracking of pavements. Recognizing the substantial impact of mechanical and environmental factors on pavement damage performance, this study considers time- and temperature-dependent deformations and fracture of bituminous mixtures. To address this, the finite element method incorporated with cohesive zone fracture was used to account for the viscoelastic properties and temperature-dependent fracture characteristics of the bituminous mixtures. The concept of multiphysics modeling is elucidated within this context. To assess the capability of the modeling approach and its sensitivity under varying pavement design variables and loading conditions, a total of 14 cases with varying mixture properties, pavement layer configurations, and loading conditions (i.e., thermal loading only and coupled thermal–mechanical loading) were considered. The computational modeling presented in this study has the scientific rigor to predict complex fracture of mixtures and pavements with promising modelling efficiency with a few laboratory tests. Model simulation results demonstrate the effects of mixture properties and their layer configurations, which implies that coupled multiphysics modeling such as herein can differentiate the pavement damage performance influenced by interactive design variables and loading conditions. The pavement failure process is intensified when thermal and mechanical loads are applied simultaneously.