Damage characteristic of asphalt mixture by permanent deformation test

In order to analyze the damage characteristic of asphalt mixture, repeated loading permanent deformation tests of two asphalt mixtures are conducted, and the damage parameters are obtained based on the test results and damage evolution equation deduced from the Kachanov damage raw. It is indicated that the mechanical model coupled with damage can well describe the whole three-phase permanent deformation of asphalt mixture under repeated loading. The damage of asphalt mixture monotonously increases with loading cycles, and the damage increases rapidly at the moment when asphalt mixture is close to failure. The value is bigger at higher temperature and stress, and also it increases faster. When loading cycles reaches the flow number, the damage values of two asphalt mixtures are 0.14-0.15. It shows that damage also exists in the migratory and stationary phases and is approximately linear though its value is small. But, it is unreasonable to ignore the damage in these two phases.