The Research On Mechanism Of Cracking Of Asphalt Pavement Under The Coupled Action Of Temperature And Load

Due to exist in the different stages of asphalt pavement that cracks is becoming a main damage mode of pavement.Current research focuses on asphalt pavement crack in fatigue cracks or reflective crack produced by the crack at the grass-roots level,and Top-Down Crack is a kind of injure that who does more harm than fatigue cracks and reflect cracks of asphalt pavement damage.Layer bottom permissible bending tensile stress as an index of crack resistance design in traditional pavement design theory, it failed to make a reasonable explanation on the Top-Down Crack in asphalt pavement,and research on Top-Down Crack mostly focused on the tire pattern type,the size of vertical load, speed and other aspect.The asphalt pavement structure play its road performance under the natural conditions,only focuses on the vertical load but ignores the horizontal load and temperature is not a true reflection stress response of bituminous pavement crevice and Top-Down Cracking mechanism.In this article, based on the linear elastic of theory, mechanics of fracture,plastoelasticity and the theory of viscoelastic,using ABAQUS finite element software simulation analysis of vertical load separately, the roles of vertical load and horizontal load meanwhile,the coupled action of temperature and load of bituminous pavement structure and Top-Down Cracking principle,and application of the theory of the maximum circumferential force calculation of Top-Down Crack tip I-II compound cracking rupture Angle.This text established the 3-D bituminous pavement structure model of pavement structure,then contrast with the general theory of layered systems analytical solution to prove its validity.Study the pavement structure load stress response under the vertical symmetrical load and partial load. Then 2-D bituminous pavement structure model of stress response is consistent with the 3-D bituminous pavement structure model,adding the Top-Down cracks to the 2-D bituminous pavement structure model, the damage apex tip define as a singular unit.By extending the finite element(XFEM) method to figure up the stress intensity factor with J integral and T stress of damage apex.Top-Down Crack tip apex for shear crack.Then introduced horizontal load in the bituminous pavement structure model,by changing the horizontal load size and horizontal load position to study its impact on the asphalt pavement structure stress and crack tip parameters of Top-DownCrack.Subjected to the horizontal load and vertical load coupled impact on bituminous pavement structure that the Top-Down Crack is compound craze,then application of the theory of maximum circumferential force calculation of Top-Down fracture Angle of crack tip.Finally draw into the factor of temperature on the bituminous pavement structure,then analysis of different initial temperature, chilling rate and final humidity impact in stress of flexible roadbed structure.By changing the depth of Top-Down Crack that horizontal load and vertical load size and its position to explore separately, and the roles of temperature and load coupling temperature crack Top-Down Cracking mechanism.