Characterization And Prediction Of Viscoelastic Behavior Of Asphalt Mixture

Asphalt mixture is a composite material obtained by mixing coarse aggregate,fine aggregate,mineral powder,asphalt and admixture at a certain temperature and then compacting,due to the randomness and heterogeneity of the structure,its mechanical behavior under load is very complicated.Under most vehicle loads,the asphalt mixture has very little strain,and its mechanical response satisfies the linear viscoelastic theory.Therefore,it is of great significance to study the linear viscoelastic response of asphalt mixtures.Based on the linear viscoelastic theory,this paper enriches and perfects the characterization and prediction methods of the existing asphalt mixture viscoelastic properties,and carries out the following research work:1.To accurately describe the static viscoelastic behavior of asphalt mixtures,using the linear viscoelastic theory,damage mechanics theory,and glue theory to analyze the creep failure process of asphalt mixture under high stress,considering the damage evolution of mixture during creep and creep failure,coupling the damage factor into the viscoelastic constitutive model of the mixture,then several viscoelastic creep damage constitutive models are proposed,these viscoelastic creep damage constitutive models are compared with the classical Zener model,Burgers model,fractional differential Maxwell model and fractional differential Kelvin model,it is indicated that these viscoelastic creep damage constitutive models can better characterize the static viscoelastic behavior of asphalt mixtures.2.To accurately describe the dynamic viscoelastic behavior of asphalt mixtures,based on the fractional differential Zener(FDZ)model,a modified fractional differential Zener(mFDZ)model is proposed.The expressions of dynamic viscoelastic such as dynamic modulus,storage modulus,loss modulus and loss tangent in the frequency domain are given,which are satisfy the Kronig-Kramers relationship.Combined with the test results of the complex modulus of the asphalt mixture at different temperatures and loading frequencies,the temperature-independent model parameters of the mFDZ model are given by Wicket diagram,the temperature-dependent model parameters were determined using the time-temperature equivalent principle and the WLF equation,then the dynamic viscoelastic master curve of the asphalt mixture was obtained.The mFDZ model are compared with the FDZ model,the Sigmoid function model,the Generalized Sigmoid function model,and the Havriliak-Negami(HN)model,it is indicated that the mFDZ model can better characterize the dynamic viscoelastic behavior of asphalt mixtures.3.To explore the relationship between static and dynamic viscoelastic properties of asphalt mixtures.Base on the linear viscoelastic theory,the relaxed modulus Prony series expression of generalized Maxwell model and the creep compliance Prony series expression of generalized Kelvin model,applying the configuration method in MATLAB software to convert the complex modulus of asphalt mixture into relaxation modulus and creep compliance.At the same time,the relevant parameters are given,the mutual conversion of static and dynamic viscoelastic mechanical properties of asphalt mixture is realized.