Research On Fatigue Damage Mechanism Of Asphalt Mixture

Fatigue cracking is one of main destruction forms of asphalt pavement. Research on fatigue performance of asphalt mixture can improve the anti-fatigue performance of asphalt mixture and prolong the service life of asphalt pavement. The phenomenological fatigue model is mainly used to study asphalt mixture fatigue performance both indoor and abroad. Fatigue life is often different under different test methods and test conditions for the same asphalt mixture, which will affect the objectivity of evaluation. Based on the asphalt beam bending fatigue experiments and the theory of asphalt fatigue damage, the fatigue mechanism of asphalt mixture was explored preliminary, The intrinsic link was found between different testing methods.Firstly, experiments of constant stress and strain beam bending fatigue under different conditions for AC13, AC20, ATB25 asphalt mixture were carried on. Fatigue equations of stress-fatigue life and strain-fatigue life were established. And analysis of the impact on the asphalt mixture fatigue life under different experiment temperature and load frequency.Then, the flexible damage parameter was defined, the fatigue evolution regulation of asphalt mixture in the process of different fatigue experiments was analyzed. It was considered that the asphalt mixture has the failure process from moving phase, stabile phase to accelerate phase. Fatigue process of asphalt mixture from the point of fatigue damage was analyzed and new failure criterion was defined.Finally, by theory analysis and fatigue experiments, the fatigue damage equation of asphalt mixture, which was irrespective with the experiment conditions such as loading control mode, experiment temperature, experiment loading frequency and so on, was established.