Propagation Of Surface Crack In Asphalt Pavement Under The Traffic Load And The Research Of Fatigue Life

Because of the asphalt concrete's porosity,as well as some problems caused in the process of construction and maintenance, there are some minor cracks in the asphalt pavement.some of these cracks may extends down and damages the pavement due to repeated vehicle load.In this paper,a 3D finite element model was established with using fracture mechanics theory and finite element method to imitate the asphalt pavement.The stress intensity factor was calculated ,the crack's fatigue life was also been calculated.In this paper,we considered the influence to the pavement when the horizontal load works together with the vertical load.the results show that compared to the vertical load works alone, when the horizontal load works together with vertical load,the stress intensity factor were sharply increased,and due to the horizontal load's influence,the stretching stress intensity factor were much greater than the shearing stress intensity factor at most time,it indicates the horizontal load is an important factor of the crack's growth,and only consider the vertical load's influence is not scientific and sufficient.Under the consideration of horizontal load,we analyzed the influence of surface thickness, surface modulus, subbase modulus, subbase thickness, we also calculated the stress intensity factors of cracks in place where vehicles ofen break and accelerate.In this paper,we use Paris law and reasonable numerical analysis method to calculate asphalt pavement's fatigue life, analyzed the variation character's influence to crack's fatigue life,and made some corresponding proposal,the calculation results can reflect the fatigue damage's process,provide reference to the prevention of asphalt pavement's surface crack and treatment.