Fatigue Cracking Analysis of Asphalt Concrete Based on Coupled XFEM-Continuum Damage Mechanics Method

Abstract

Fatigue cracking is a major distress in asphalt concrete and has a significant influence on material performance. A coupled extended finite element method (XFEM)-continuum damage mechanics (CDM) model was developed in this paper to investigate fatigue cracking behavior of asphalt concrete. The model was then implemented in commercial finite element software using user-defined subroutines (UMAT and UDMGINI). This model successfully simulated the fatigue damage accumulation stage and crack propagation stage as a continuous process. Determination of model parameters are discussed, and then fatigue crack growth in a semicircular bending (SCB) beam is analyzed. Numerical results of fatigue crack growth in the SCB quantitatively matched well with experimental records. This indicates that the coupled XFEM-CDM method developed in this paper can serve as an effective tool for predicting fatigue cracking behavior of asphalt concrete. Fatigue cracking behavior and mechanical response of a three-point bending beam are also studied. Numerical findings of fatigue cracking lives and stiffness evolution are qualitatively consistent with laboratory results.