DAMAGE OF SURFACE LAYER OF ASPHALT CONCRETE PAVEMENT UNDER LAUNCHING IMPACT LOAD

A 4s a viscoeslastic material, asphalt concrete’s fatigue damage properties are studied more widely than its impact damage properties. To consider the mid/low-strain rate response produced under launching loads, a three-dimensional simplified ZWT (Zhu-Wang-Tang) model is used to denote material constitutive properties at the impact site. The ZWT model is a non-linear viscoeslastic constitutive relationship, established based on Cauchy strain. Based on the above constitutive model, strain-rate dependent evolution damage model, and their incremental expressions, a user subroutine for the material is compiled and integrated into finite element software. A simplified ZWT model with damage under conditions of unchanged strain rate is deduced and its parameters fitted by the least squares method. The variation law and distribution law of damage are clarified by analyzing impact damage in the surface layer of the asphalt concrete launch site, and the conclusion can serve as a reference in choosing launching sites.