Analysis On Reflection Crack Extension Of Hot In-place Recycling Asphalt Pavement

Hot in-place recycling technology is a one-time realization within a certain depth of the surface which is the regeneration technology of old asphalt concrete pavement.At present,there are many experimental studies on fatigue and fracture properties of thermal regenerated materials,whereas the numerical simulation of fatigue fracture of thermal regenerated materials is still limited.Therefore,the fatigue and fracture process of the pavement structure of hot inplace recycling materials is studied by numerical simulation in this paper.In this paper,first of all,three point bending fracture experiments of asphalt mixture trabeculae are simulated by finite element method.The whole process of the trabecular fracture is simulated by the cohesive zone model and the extended finite element model respectively,and the simulation results are compared with the experimental results to verify the accuracy of the simulation results.Then,through sensitivity analysis,the influence of the parameters in the extended finite element model on the three point bending trabeculae fracture experiment is studied.The finite element simulation of the four-point bending fatigue test of asphalt mixture trabeculae is studied in this paper.In order to simulate the fatigue process of mixture,the material subprogram of fatigue damage with maximum principal strain as independent variable is compiled by ABAQUS software in this paper.The fatigue process of four-point bending trabeculae is simulated by the material subroutine.In addition,the simulation results are verified by test data,and the sensitivity of material parameters of fatigue subroutine is analyzed.Then,the extended finite element method and fatigue subroutine are combined to realize the joint simulation of fatigue and fracture of mixture in the paper.The experimental and simulated results of controlled-stress four-point bending trabeculae show that the model is effective in fatigue and fracture simulation.Finally,the fatigue damage analysis of the simulated common pavement structure is carried out by the developed fatigue damage material subroutine.The damage evolution process of the whole pavement structure containing hot in-place recycling materials and the main influencing factors are obtained.Then through the combined fatigue fracture simulation program,the expansion of the initial crack under the repeated load is analyzed,and the effect of the initial crack position on the crack propagation of the pavement structure is obtained.The research results of this paper reveal the inherent law and rules of fatigue fracture of the pavement structure of hot in-place recycling materials,and provide the theoretical basis for preventing the fatigue fracture of hot in-place recycling materials.