Traffic Loads Of Asphalt Concrete Pavement Failure Analysis

The rapid increasing of road traffic and vehicle load in our c ountry, life of asphalt pavement is shorter, the traffic load become s the major influence factor, Road asphalt mixture inevitably exist s slight defects or cracks, repeat the role of vehicle load in the cr ack tip cause by stress concentration and complex form expansio n, eventually lead to fatigue cracking road。Based on the analysis of asphalt concrete road surface cracking and expansion,The main contents are listed as follows:1)The author uses the shell theory and fracture mechanics,doin g theoretical analysis to the down-layer of the road surface layer of micro-cracks,establish theoretical model to analyze the variation of the stress intensity factor in the change of the road surface mo dulus and the thickness of surface layer.2)Establish the finite element model of the cracks of asphalt concrete pavement,consider the symmetric and asymmetric loading and the change parameters on the surface layer thickness,surface 1 ayer modulus,the thickness of the grassroots,sub-base layer and the overload.obtained the corresponding stress intensity factor,analysis the parameter variation and relationship between them.3)Using Paris equation and numerical integration method also the finite element analysis method,caculated the down-layer of asp halt concrete road surface crack fatigue life,analyzing the sensitivi ty of the pavement fatigue life to different structural parameters.This thesis analyzes the influence of the pavement under traff ic and vehicle load on the fatigue propagation rules and fatigue li ves of on the structural parameters,overloading,non-uniform distribu tion,proposes some recommendations about pavement material selec tion and structure design.Research have done show that the fatigue lives of asphalt pavement decrease rapidly for the increment of 1 oad and non-uniform distribution of load resulted from overload.Th e author put forward the further work in this discussion based on the problems still exist in asphalt pavement.