Analysis of fatigue crack growth behavior in asphalt concrete material in wearing course

Fatigue crack is a main form of structural damage in flexible pavements. Under the action of repeated vehicular loading, deterioration of the asphalt concrete materials in pavements, caused by the accumulation and growth of micro and macro cracks, gradually takes place. The indirect tensile fatigue testing (ITFT) was carried out on three types of asphalt concrete materials comprising a high stiffness Gilsonite modified wearing course (GM-ACWC), stone mastic asphalt (SMA) and conventional asphalt concrete wearing course (ACWC) to establish fatigue damage model and failure criteria. Fatigue damage model, based on continuum damage approach, to describe the formation of micro-cracks and crack propagation was developed for the wearing course materials. With the fatigue damage model, finite element analysis was carried out to study the crack resisting performance of the three wearing course materials in a flexible pavement structure.