Study On Nonlinear Fatigue Damage Characteristics Of Asphalt Mixtures Under Stress And Strain Control

Research on the fatigue behavior of asphalt mixture in the stress and strain control mode has been a research difficult.Due to different loading modes of the two control modes,the fatigue life will show a big difference,and the material fatigue performance can not be compared quantitatively.The selection of different fatigue modes also makes the asphalt mixture fatigue failure standard not uniform and different fatigue failure The standard of fatigue performance of asphalt mixture will inevitably cause trouble;for the fatigue properties of asphalt mixture,there is no uniform method of fatigue test,which resulted in different researchers have poor test data comparison,the reference value is not Big.In this paper,aiming at the objective fact that the two control modes of stress and strain are different from each other,a new fatigue test method is proposed to systematically study the fatigue performance of asphalt mixture in order to analyze and evaluate the fatigue performance of asphalt mixture more comprehensively.The ultimate tensile stress(tensile strain)of the specimen was determined by uniaxial tensile strength test to select the reasonable range of stress level(strain level)to carry out the fatigue test,and then the stress control mode specimen fatigue failure point According to the range of attenuation amplitude of the mean value of the initial modulus and the mean value of the critical modulus in the stress control mode,the fatigue failure points of the specimens under the strain control mode are clarified,and the failure criteria of the two fatigue modes are unified.Based on the unified fatigue failure criterion,the fatigue equations under different control modes,different stress levels(strain levels)and different factors were established.The applicability of fatigue factor models with different factors was compared and analyzed.The results show that the strain fatigue equation has a better correlation,This is contrary to the current practice of using stress-fatigue equations.The uniformity of the nonlinear fatigue damage model under two control modes is deduced and verified.The stiffness decay curve and the fatigue damage factor evolution curve are obtained under the two control modes.The fatigue damage factor and the stiffness decay curve are revealed under the two control modes The evolution of law.In view of the common difference of fatigue damage curves of asphalt mixture under stress and strain control mode,the fatigue failure and fatigue damage characteristics are analyzed in detail.The results show that the fatigue process of the specimens both experienced rapid growth and stable development The change of stage and the stage of rapid destruction are not obvious in the tensile fatigue test.The fatigue process of the specimens under the two control modes is also different,mainly showing the difference in the third stage(the stage of rapid destruction).Based on the stress and strain control mode to establish asphalt pavement fatigue performance evaluation system for the analysis and evaluation of asphalt mixture fatigue performance,not only for the unified indoor fatigue test methods have a catalytic effect,the fatigue properties of asphalt pavement more of a certain reference value...