Comparative Analysis Of Fatigue Text Methods Of Asphalt Mixture

During the pavement experiencing repeated wheel load,stress and strain in long-term alternating state,resulting in the pavement strength gradually decreased.When the load is repeated more than a certain number of times,the stress of pavement under the action of the load will exceed the strength decrease after the structural resistance,so that the pavement fatigue failure.At present,the pavement fatigue failure phenomenon has been paid more attention by road workers both at home and abroad,a large number of research on fatigue performance of asphalt mixture has been come up to.In this paper,on the basis of previous studies,the currently numerous asphalt mixture fatigue performance research methods have been compared and summarized.Based on the traditional phenomenological method,beam bending test,semi-circular bending test and indirect tensile test of three kinds of test methods is selected.Through the finite element analysis method of ANSYS,the finite element model of three kinds of test methods are established,and the stress and displacement state of the three models are compared and analyzed.Using AC-13,AC-20,AC-25,SMA-13,SMA-20,ATB-25 six kinds of gradation mix design,through high temperature stability and water stability test the optimum asphalt aggregate ratio.Consider the nominal maximum particle size,porosity of mixture,stress level,test temperature and test frequency by orthogonal design.The strength test and fatigue test of three kinds of test methods are completed according to the design plan.Three test strength performance: the semi-circular bending specimen>small beam bending specimen>indirect tensile specimen.The fatigue life performance: indirect tensile test>small beam bending test> semi circular bending test.The range analysis and variance analysis of the fatigue life of the three tests were carried out,the results show that the different test methods,the influence of various factors on the fatigue performance is not the same.Finally,the fatigue response model was established by the multiple linear regression method,and the regression equation was obtained.By comparing the three kinds of fatigue test analysis method,study on fatigue performance of the asphalt mixture is recommended to use the semi-circular bending fatigue test.