Study on Compound Type Crack Propagation Behavior of Asphalt Concrete

摘要

The furthest dangerous cracking type of asphalt pavement is usually considered of the simplex Ⅱ type crack(namely shear crack) under traffic load, but the so-called Ⅱ type crack should be the compound cracking at the concurrence of Ⅰ type crack (namely splay crack) and Ⅱ type crack. In order to study the compound type crack propagation behavior of asphalt concrete, a three point bending beam with compound type notched has been designed. Asymmetry-gap small girder specimens of asphalt concrete are adopted in the test, and the central testing equipment is MTS. A series of compound type three point bending beam tests have been performed to simulate compound type crack initiation and growth. The propagation of compound type crack is studied by a newly developed numerical code, Rock Failure Process Analysis (RFPA~(2D)).it is shown that the crack initiation angle and the peak load increased as the distance of the preexisting crack from the midpoint of the beam increased, the crack propagation path follows some regularity in general and the main force of crack propagation is still tensile stress. Through this work, the understanding of the mechanism about damage and early destroy of asphalt pavement can be advanced and it can provide guidance for asphalt pavement design and maintenance.