Study On Lateral Crack Propagation Characteristics And Fatigue Life Of Asphalt Pavement In Large Temperature Difference Area

As the asphalt pavement has been subjected to the repeated action of the external natural environment and vehicle load for a long time,various forms of diseases will occur,and cracking,as one of the main forms of damage,will cause serious damage to the continuity and integrity of the asphalt pavement structure.Aiming at the asphalt pavement with surface temperature shrinkage cracks in large temperature difference areas in China,the temperature load and the crack propagation characteristics under moving wheel load can be studied,which can reveal the crack propagation behavior of asphalt pavement more deeply,and the design of asphalt pavement in this area.Construction,and post-operation and maintenance have certain guiding significance.In this paper,the finite element model of asphalt pavement with initial surface transverse crack is established.Based on the basic theories of fracture mechanics and heat transfer,the finite element analysis software ABAQUS is used to study the transverse crack on the surface of asphalt pavement at temperature.The crack propagation characteristics under moving wheel load are analyzed,and the effects of various factors on the fatigue fracture life of Top-Down cracks in asphalt pavement are analyzed.The main research work includes:(1)Establishing the finite element model of asphalt pavement with initial transverse crack on the surface,combined with the summer and winter temperature conditions in the large temperature difference region of northwest China,the temperature field changes of asphalt pavement under two kinds of temperature conditions are analyzed;The tenperature field results were used to study the crack propagation characteristics of the transverse cracks of asphalt pavement in the 24-hour period under two temperature conditions,and then the influence of the temperature-cooling cycle on the crack propagation of the surface transverse cracks was discussed.Based on the extended finite element method,randomized The aggregate application technology was applied to the establishment of the mesoscopic model of asphalt mixture,and the expansion process of the surface crack under the temperature stress was simulated.(2)Based on the finite element model of asphalt pavement established above,the crack propagation characteristics of surface transverse cracks under moving wheel load are analyzed under the conditions of temperature field of high temperature and low temperature asphalt pavement.The lateral cracks of moving wheel load are analyzed.The influence of crack propagation on the point is studied.The effects of traffic load(shaft weight,vehicle speed,emergency braking and acceleration and deceleration state),base layer modulus and thickness,and interlayer bonding state on the crack propagation and propagation characteristics of the surface transverse crack are studied.(3)Based on the calculation of the stress intensity factor at the crack tip at each depth,the relationship between the crack propagation depth and the number of vehicle wheel loadings is studied based on the complementary Paris formula.The traffic load(axis is calculated and analyzed by linear approximation method).The effects of various factors such as weight,speed,emergency braking and acceleration and deceleration),base layer modulus and thickness,and interlayer bonding state on the fatigue fracture life of Top-Down cracks in asphalt pavement.