Study On Shear Fatigue Life Of Asphalt Mixture Considering Damage Based On DEM

Our country’s transportation field including the highway construction field has developed rapidly in recent years.The highway construction field has achieved a series of achievements,however,it is also facing some new challenges.With the increase of highway use time and the increase of vehicles,especially heavy-duty vehicles,many asphalt mixture pavements have suffered from cracks and other diseases before reaching the design service life and faced with fatigue damage and require maintenance or renovation.In early China,the fatigue failure mode of asphalt pavement was bending fatigue failure,and its failure mode was mainly bottom-up cracks.Nowadays,due to the use of semi-rigid bases on asphalt pavements and the increase of heavy-duty vehicles as a result of the development of China’s economic construction has made asphalt pavement shear fatigue damage the mainstream form of damage,and the main failure mode has changed to top-down cracks.Therefore,the shear fatigue failure of asphalt pavement needs more researchers to study.This study use CT scanning technology and digital image processing program of Sub-Microstructure Analysis System of Asphalt Concrete(MAS AC)to obtain the information of each component in the asphalt mixture.And these particles are assigned to the three-dimensional discrete element software PFC3D to establish a uniaxial repeated penetration model.Using the principle of Frequence-temperature-Superposition(FTS)and the introduction of the damage,program with the PFC3D embedded FISH language to add damage factors D and temperature gradient to the uniaxial repetitive penetration model to obtain the shear fatigue life of the asphalt mixture.Comparison of values verifies the feasibility and accuracy of using this model to simulate the shear fatigue life of asphalt mixtures.The internal structure image of the asphalt mixture obtained by CT scanning technology is also processed to obtain the number of contact points in the asphalt mixture,and to explore the relationship between the number of contact points and the shear fatigue performance of the asphalt mixture.The research results show that it is feasible to use three-dimensional discrete elements to simulate the shear fatigue life of asphalt mixtures;the fatigue life of asphalt mixtures considering the damage factors makes the simulation results more accurate;temperature gradient has a certain effect to shear fatigue life;the shear fatigue life of asphalt mixture is related to the number of internal contact points of asphalt mixture.