The Research On The Static And Dynamic Creep Model Of Asphalt Mixture Under Uniaxial Pressure

Asphalt mixture is a typical kind of thermo viscoelastic material, which is the kind of amorphous and having pretty complicated internal structure material.Many important development on the studies of viscoelastic theory have been made by the efforts of scholars at home and abroad, who have made their efforts to study the deformation relations of the material properties, which was external force, temperature, load time, loading rate and so on. Meanwhile, they have studied some regularities of stress fields and strain field in asphalt mixture viscoelastic domain. Linear viscoelasticity theory has sufficiently developed, while nonlinear viscoelastic theory is still under developed by the reason of difficulties in experiment and mathematics, as the research about asphalt mixture further studied.The aim of this paper is to seek the regularities while the stress and strain of the asphalt mixture changed and developed at particular situation.The chosen asphalt mixture material was grade AC-13C and 90 asphalt.We derived a experience constitutive equation of the asphalt mixture under static uniaxial creep test at a specific environment which was based on optimal theory calculate. Then we comparing the results of the optimal equation to the traditional mechanical models results, obtained the experience constitutive equation which has higher precision and wide applicability. In order to better description the nonlinear viscoelastic physical meaning of asphalt mixture, the paper present a new mechanical model, and described the deformation mechanism of the model, then it obtained higher precision and more clearly physical meaning. We derived a expression of constitutive equation about stepcreep of asphalt mixture by multiple integral according to the test at a particular situation. Meanwhile, we calculated the creep compliance of the model and introduced the expression of other multiple integral.We presented a Nishihara Model according to the creep test, and used Kachanovs creep damage formula to global coupling, as a result, the damage was related with stress level.According to the stress control of fatigue test, we analysisd the viscoelastic dynamic constitutive of asphalt mixture to present a critical fatigue and a nonlinear fatigue damage equation of asphalt mixture which was based on plastic strain. As a result, the equation can simulate its damage evolution better than the traditional way.