Study on the Fatigue Residual Strength and Damage Evolution of Asphalt Mixtures Under Different Stress States
At present,the research on the fatigue characteristics and damage evolution laws of asphalt mixtures in China and abroad is not sufficiently deep,resulting in inaccurate evaluation of the remaining life of structural layers.Therefore,dynamic load strength tests of asphalt mixtures under different temperatures and stress states were conducted,and the applicability of maximum tensile stress,Tresca,Mises,Drucker-Prager,Bresler-Pister,and simplified Desai strength models were analyzed based on this.The results show that the Bresler-Pister elliptical strength envelope and simplified Desai hexagonal envelope are in good agreement with the tensile,compressive,and splitting strength test points.Based on this,considering the effects of temperature and loading speed,the strength envelopes were obtained.Then,the fatigue life of the mixture was measured at different temperatures and stress levels.The specimens with loading times of 20％,50％,65％,and 80％fatigue life were selected for tensile,compressive,and splitting residual strength tests.Based on this,the Bresler-Pister and simplified Desai envelope were used for the first time to characterize the three-dimensional strength decay law.Furthermore,by defining the residual three-dimensional strength,loading times ratio,and other parameter groups,the internal unity of three-dimensional strength failure and fatigue failure was realized based on the damage evolution model established by the preferred Bresler-Pister criterion.The results of this study provide an important experimental and theoretical reference for predicting the residual strength of asphalt layers with different service lives,as well as fatigue load control in life extension design.
pavement engineeringasphalt mixturefatigue residual strengthdamage evolution lawdifferent stress states
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