Numerical Analysis Of Epoxy Asphalt Mixture Performance Based On Mesostructure

Epoxy asphalt mixture composed of epoxy asphalt,aggregate according to certain proportion and it is a type of thermosetting material,it has been used in steel bridge pavement widely.Considering that epoxy asphalt mixture is a heterogeneous composite material,its mechanical properties are not only related to epoxy asphalt binder,porosity and so on,but also influenced by the spatial distribution of these factors,that is,macroscopic properties of the epoxy asphalt mixture are the corresponding functions of the meso-structural properties of the constituent materials.In general,the effect of conventional laboratory tests about these factors is difficult to be realized.Therefore,the influence of meso-structural factors of the mixture performance is analyzed by discrete element method.Firstly,a two-dimensional digital specimen generation program of epoxy asphalt mixture with coarse aggregate gradation,mastic and porosity was prepared by using the "Fish"language built in the discrete particle flow program;In order to obtain the relevant parameters of epoxy asphalt material,the composition design of two different flexibility of epoxy asphalt mastic and the indoor static uniaxial creep test were carried out,the Burgers model was used to fit the creep compliance curve of epoxy asphalt mastic and to stimulate the viscoelastic parameters.According to the physical meaning of each microscopic parameter in the discrete element,the conversion relation between the macroscopic parameter and the microscopic parameter was established.Secondly,combined with the characteristics of the contact model in the discrete element and the mechanical characteristics of the composition of the epoxy asphalt mixture,the appropriate contact model was selected for the epoxy asphalt mixture,and epoxy asphalt mastic virtual creep test was made by the discrete element two particle models,which corrected the parameters of the microscopic parameters and verified the correctness of the embedded Burgers model.At the same time,the uniaxial static creep test of the epoxy asphalt mixture was simulated based on the time-temperature equivalence principle,which further confirmed the reasonability of selected contact model and related microscopic parameters.Finally,the uniaxial compression test and the splitting test of epoxy asphalt mixture were carried out based on the established digital specimen and contact model of epoxy asphalt mixture,and the reliability of the virtual test method was verified by comparing with the indoor test results.Then,the effects of different gradation,void and coarse aggregate percentage composition and coarse aggregate spatial distribution on the mechanical properties of epoxy asphalt mixture were studied.Based on the virtual test of epoxy asphalt mixture,the motion characteristics of coarse aggregate particles and mastic particles in the process of uniaxial compression test and splitting test were analyzed,and the variation of contact force,displacement and velocity of coarse aggregate and mastic during loading were quantified.