Research On Prediction Model Of Typical Asphalt Mixture Dynamic Modulus Based On Discrete Element Simulation

Asphalt mixture is widely used in road construction,and its dynamic modulus is one of the important parameters of asphalt pavement design.The current "Highway Asphalt Pavement Design Code" proposes that the design level two can be predicted using an empirical prediction model.However,since the asphalt or gradation type used in asphalt mixtures has certain regional characteristics,the semi-empirical prediction model in specification level 2 puts forward the prerequisites for asphalt types suitable for road petroleum asphalt and conventional grading asphalt mixtures.Therefore,the practical applicability of the model in Jilin needs to be evaluated.Therefore,it is of great research value to propose a parameter measurement model that is simple and has a dynamic modulus prediction model for regional characteristics.Therefore,this study intends to propose a virtual dynamic modulus test method based on discrete elements and other tools,and to propose a dynamic modulus prediction model in Jilin Province.Firstly,the dynamic modulus and phase angle of the mixture are measured under the temperature and different frequency test conditions of three types of asphalt mixtures commonly used on the upper and lower layers of the typical asphalt pavement in Jilin Province.The main curve of the mixture at each test temperature was analyzed by this study,and the simoidal model of the main curve was obtained by least square fitting,and the viscoelastic mechanical properties of the mixture were evaluated.Then,based on the laboratory test results,a virtual discrete element model is constructed.This study believes that asphalt mixture is a three-phase mixture composed of coarse aggregate,asphalt mortar and voids.Then,through the combination of MATLAB and Fish language,coarse aggregates with irregular shapes were generated,and a discrete element 3D model of asphalt mixture void simulation between the coarse aggregates and given to the test piece.The composition unit can reflect the parameters and contact model of its true mechanical behavior.Through the relevant experimental analysis of asphalt mixture and asphalt mortar and the establishment of the conversion method between the macro test parameters of the asphalt mixture,and according to different laboratory tests to determine the mesoscopic composition of the various mixtures Mechanical parameters.Finally,the above modeling method was used to construct a discrete element virtual specimen model,and a virtual test of the dynamic modulus of asphalt mixture was carried out by servo loading,and the effectiveness and rationality of the virtual test were verified by relevant indoor tests.Sex.A dynamic modulus test with multiple influencing factors was carried out,thereby establishing a dataset of dynamic modulus.And the applicability of the existing dynamic modulus prediction model in the Jilin area is discussed,through regression analysis and combined with the prediction of the dynamic modulus at home and abroad The formula establishes a model for predicting the dynamic modulus.