Study On Permanent Deformation Of Asphalt Mixture Under Triaxial Repetitive Load

With the continuous formation of China's highway network,the permanent deformation of asphalt pavement is becoming more and more serious.The permanent deformation of asphalt mixture is one of the major diseases of high grade asphalt pavement,especially the harsh weather conditions and the repeated role of vehicle load makes rut happen frequently,affecting the use of asphalt pavement performance,service quality and traffic safety.At the same time with the permanent deformation of the accumulation,it will cause serious damage to the pavement structure ultimately,and its formation mechanism has a great relationship with temperature,vehicle load,axle load and other factors.Based on this problem,this paper proposes a three-axis repeated load test to evaluate the anti-permanent deformation behavior of asphalt mixture,and estimate its permanent deformation considering the actual situation of our country and the existing test conditions in our country.In this paper,the mechanism and regularity of permanent deformation of asphalt mixture are analyzed from two aspects of experiment and theory.The permanent deformation analysis of AC-13,AC-16,AC-20 and AC-25 asphalt mixtures was carried out by simulating the force of the actual pavement by triaxial repetitive load test.In this paper,the regular deformation of different asphalt mixtures was obtained by controlling the test temperature and bias stress of asphalt mixture,and the difference equation was fitted by mathematical method.The main research results are as follows:(1)The viscoelastic model of asphalt mixture under triaxial repetitive load creep test is obtained by deriving the modified Burgers model.(2)Based on the test results of the triaxial repetitive load test,simulate the experimental data by using the least squares method and the Bugers model.The mechanical model fitting parameters of the asphalt mixture were obtained by fitting the viscoelasticity model,thus establish the asymptotic model of asphalt mixture.(3)According to the prediction model of permanent deformation of asphalt mixture,the three-dimensional surface of "cyclic times-partial stress-permanent deformation" at different temperatures was established by 3D interpolation and fitting of Matlab software.Through the three-dimensional surface can be found at any temperature and partial stress level of four kinds of asphalt mixture of permanent deformation.