Experimental Research On Visco-Elastoplastic Constitutive Model Of Asphalt Mixture With Steel Slag

Using steel slag as the asphalt mixture aggregate can effectively improve the performance of the asphalt mixture,and also solves the problem of effective utilization of the steel slag,fulfills resource conservation and environmental harmony,and achieves the requirements of sustainable development.Therefore,it is of great significance to study the preparation and mechanical properties of steel slag asphalt mixture.In this paper,steel slag is firstly used as coarse aggregate to make steel slag asphalt mixture specimens,and the compression creep test is carried out under different loads and temperatures.Then appropriate constitutive models are proposed for the recoverable deformation and permanent deformation of steel slag asphalt mixture,and the applicability of the constitutive models is verified at different temperatures.Considering the influence of aggregate randomness on the mechanical behavior of asphalt mixture,a stochastic constitutive model of steel slag asphalt mixture was proposed,and the deformation of asphalt mixture under different loading conditions was predicted,which verified the feasibility of the model.Considering the difference of steel slag and limestone aggregate,the optimum whetstone ratio of steel slag asphalt mixture was determined by sample preparation.According to the determined ratio,steel slag asphalt mixture specimens were made in batches,and a series of compressive creep tests were carried out on them,which provided a basis for the study of visco-elastoplastic constitutive model of steel slag asphalt mixture.The total creep strain of asphalt mixture can be decomposed into two parts:recoverable deformation and viscoplastic deformation.The Schapery model is used to describe the recoverable deformation and Swchartz model is improved to describe the viscoplastic deformation.According to a series of compression test data,the model parameters are determined at different temperatures,and the results show that the model is suitable for describing the creep behavior of steel slag asphalt mixture at different temperatures.After determining the viscoelasto-plastic constitutive model,the experimental data of steel slag asphalt mixture at room temperature(25 ℃)were fitted in batches,and the model parameter samples were established.The random parameters were determined by statistical analysis,and the normal distribution was used to describe the distribution law of the parameters.The results show that the random constitutive model in this paper can predict the deformation properties of specimens under arbitrary stress loading history within a certain range,which well reflects the randomness of the mechanical properties of asphalt mixture,and the determined random parameters can reflect the dispersion of materials.