Evaluation of fatigue crack behavior in asphalt concrete pavements with different polymer modifiers

Fatigue crack has been recognized as one of the main forms for structural damage in asphalt concrete pavements. Under the action of repeated vehicular loading, deterioration of the asphalt concrete (AC) materials in pavements, caused by the accumulation and growth of micro and macro cracks, gradually takes place. Existing prediction models in asphalt concrete pavement typically do not take the interaction and dependencies between micro and macro mechanics into account. In this research, the fatigue damage models and failure criteria are established based on the Indirect Tensile Fatigue Tests (ITFT) and Indirect Tensile Stiffness Modulus (ITSM) tests carried out on AC materials with different kinds of polymer modifiers. These additives are Polypropylene (PP), Crumb rubber (CR), Cellulose fiber (CF), Asbestos fiber (AF) and Gilsonite (GS). Fatigue damage model, based on continuum damage mechanics, describes the formation of micro-cracks and crack propagation developed in the wearing course materials (ACWC and SMA). With the fatigue damage models, finite element analysis is carried out to study the crack resisting performance of the wearing course materials in a flexible pavement structure.