Numerical Analysis Of Reflection Cracks Propagation In Semi-rigid Base Of Asphalt Pavement By XFEM

At present,hydraulic binder treatment stabilized crushed gravel is mainly used as the semi-rigid base material of asphalt pavement in our country;however,due to the influence of external factors of construction and the internal characteristics of road materials,the initial crack of the semi-rigid base can be easy to produce.Once the base cracks,various factors including traffic load,temperature,humidity and so on lead to the crack tip stress concentration,which causes the crack extending to the direction of the surface layer and accelerating the process of damage of the pavement structure.It seriously affects the long-term service performance and service life of asphalt pavement.Therefore,it is of great significance to study the crack propagation of semi-rigid base.For the propagation of the reflection cracks in the semi-rigid base of asphalt pavement,most of the previous researches only considered the effect of traffic load and very few considerd the impact of temperature,yet the effect of traffic load coupling with temperature was hardly researched,on the other hand,the traditional finite element numerical simulation method was applied,whose poor calculation accuracy made it unpopular.In addition,when it comes to the interlayer contact situation,the existing researches often employ the friction coefficient for characterization with the disadvantage of simulating the static contact situation only.What's more,most of the previous researches regarded the asphalt mixture as linear elastic or viscoelastic material with even less focusing on the effects of dynamic modulus considering the effects both of the loading frequency and temperature.As described above,this paper takes advantage of XFEM(extended finite element method)in ABAQUS to simulate the crack propagation of asphalt pavement,and the dynamic modulus of asphalt mixture considering the loading frequency and temperature is applied.Taking account of the interlayer condition with the theory of delamination progressive damage failure,the crack propagation in the semi-rigid base of asphalt pavement is analyzed,and the main contents are as follows:(1)The reflection cracks propagation model of semi-rigid base asphalt pavement is established using XFEM in ABAQUS,and the dynamic modulus considering the effects of loading frequency and temperature is applied,considering two situations:cracks extending to and not extending to the surface layer.(2)The model described above is employed to analyze the reflection cracks propagation of semi-rigid base under dynamic traffic load individually,considering different factors and applying the delamination failure theory to character the interlayer states.(3)The model described at(1)is employed to analyze the reflection cracks propagation of semi-rigid base focusing on the cyclical and non-periodic temperature individually,considering different factors and applying the delamination failure theory to character the interlayer states.(4)The model described at(1)is employed to analyze the reflection cracks propagation of semi-rigid base under dynamic traffic load combining with the cyclical and non-periodic temperature,comparing the result of the situation of reflection cracks propagation and propagation life of fatigue based on Paris Law under different situations of(2)and(3).