A Theoretical Analysis of Fatigue Cracking in Flexible Pavements

Abstract

This paper examines theoretically the possible mechanisms of fatigue cracking in asphalt pavements using linear elastic fracture mechanics (LEFM). The effects of a non-uniform transverse contact traction between the tyre and pavement on longitudinal surface fatigue cracking are examined theoretically using a finite element (FE) pavement model. Fatigue cracking due to thermal loading is also examined using a simplified linear viscoelastic pavement model. Results indicate that the non-uniform transverse contact traction produces short surface cracks (10 mm) but does not lead to significant pavement fatigue. However, for these short surface cracks, the combined vehicle and thermal load cycles may produce conditions that are favourable for fast fracture. Fatigue cracking (both longitudinal and transverse) at the base of the asphalt layer is found to be mainly dependent on the pavement geometry and the magnitude of the normal load.