Research On Deformation Characteristics And Damage Characteristics Of Asphalt Mixture Under Different Stress Pattern

Asphalt mixture, as a viscoelastic material, will deform under the external environment and the role of traffic load, which cause the internal structure damage of asphalt pavement. With the increase of the number of load, the deformation will continue to accumulate, damage will be evolving, ability to resist deformation of pavement structure and material will decay. Even in the same load, the mechanical response of asphalt pavement will change dramatically. Mixture stiffness modulus and strength values are measured different under different test methods and different loading rate. However, different values of modulus and strength will greatly affect the pavement layer calculation results of stress, strain and displacement, thus seriously affecting asphalt pavement design.Deformation characteristics and damage characteristics of asphalt mixture under different mechanical test methods has important theoretical significance and application value, which can reveal the destruction reasons of asphalt pavement materials under loads of different mode of action.Asphalt mixture dynamic modulus change with load level, then the law of dynamic modulus changed with stress level is obtained, the maximum dynamic under modulus of direct tensile test, compression test, indirect tensile test and bending tensile test are obtained respectively in 0.37MPa, 0.38MPa, 0.14MPa and 0.88MPa. Finally, dynamic modulus master curve under different loading modes was studied.Surface materials deformation under constant stress is studied by the static creep test, three creep damage equation are derived and establishment, and Burgers model is modified by damage model, the results prove that the creep deformation process can be better characterized by Burgers model.Asphalt mixture destruction features are research the intensity under different loading rates. The relationship between strength and loading rate is obtained, asphalt mixtures strength values and specimen cross-section shape are different under different test conditions.Compression test of asphalt mixtures is simulated as a cylinder, Numerical simulation results show that the strength of asphalt mixture increases with the loading rate increases rapidly first, followed by gradual smooth, presenting on the power function form, Numerical simulation results are consistent with indoor test results. Porosity decreases first and then increases with increasing loading rate.