Numerical Simulation And Mechanism Study For Reflective Crack Of Asphalt Pavement With Semi-Rigid Basement Asphalt

Reflective cracking is one of the major modes of damage in asphalt pavement. Under the repeated vehicle load or low temperature, the micro cracks of asphalt pavements propagate, increase, coalesce, and finally form eyeable cracks, which results in structural distresses of asphalt pavements. It is very necessary that study on the mechanism of the pavement damage and early breaking are conducted, and the procedure of cracks propagation are analyzed, which can strengthen the crack resistance of the asphalt pavement structure, improve the present design methods.In this thesis, the effects of traffic loading and temperature loading on crack in the base of asphalt pavement have been analyzed. Firstly, based on the viscoelastic theory, general Maxwell model was used to simulate the asphalt mixture viscoelastic property. Secondly, according to the theory of heat transfer, the model of FEM which contains through check is created, and the influence of ambient temperature on the stress field of pavement system is analyzed. Moreover, the influences of varied cooling rate and amplitude on the stress intensity factor (DSIF) of crack tip are also discussed. The analysis indicates that the low temperature circumstance will cause that the region of high stress appear in the crack tip. Under repeated temperature load, microcracks in the base maybe propagate to the face, and form the surface crack. Thirdly, the performance of dynamic stress intensity factor was discussed under vertical load with different vehicle velocity, rebound modulus and damping ratio by FEM simulation. The influence of DSIF with both horizontal and vertical load was analyzed. The numerical results show that the value of DSIF decreased with increase of the vehicle velocity and the damping ratios. The value of DSIF increased rapidly with increasing of the base modulus. The peak point of the DSIF increased with both horizontal and vertical load, which would influence the shear stress and tensile stress of the road.Through comparisons with the results of indoor test and FEM numerical analysis, we found that adding cellulose fiber is a very economic and effective method to suppression propagation of the reflective crack.