The Research On The Anti-cracking Of Asphalt Pavement With The Asphalt Rubber Stress-absorbing Layer

Semi-rigid base asphalt pavement is the major form of the asphalt pavement in China, but semi-rigid base material can produce temperature contraction crack and dry shrinkage crack, which can further propagate to the surface layer from semi-rigid base and produce reflective crack. In this paper, asphalt rubber stress absorbing layer is added between the surface layer of asphalt concrete pavement and semi-rigid base to achieve the purpose of preventing and controlling reflective crack, on the basis, the following aspects of research are carried out:Firstly, systematic research on the theory of stress intensity factor and the application of crack in the asphalt pavement is conducted; secondly, on the basis of consideration of interlayer contact,3D finite element model of crack rubber asphalt stress absorbed layer is established; the anti-cracking mechanism of rubber asphalt stress absorbed layer is researched; the influence on crack propagation is analyzed by changing the parameters of the rubber asphalt stress absorbing layer; besides, the change rules of the tensile stress shear stress and road deflection at the bottom of each structural layer upon asphalt concrete pavement layer as well as the stress intensity factor of crack tip are considered; finally, the best elasticity modulus and thickness of rubber asphalt stress absorbing layer are figured out.The influence of tensile stress and shear stress of each layer of asphalt concrete pavement under the action of heavy-duty transportation and different tire pressure is analyzed, The results show that the heavy-duty transportation has great influence on the damage to asphalt concrete pavement; the influence can be alleviated by setting the rubber asphalt stress absorbing layer and the reflective crack can be greatly reduced. Besides, the reasonable thickness and elasticity modulus of of rubber asphalt absorption layer and its influence on asphalt concrete pavement under the action of heavy-duty transportation is analyzed by using ABAQUS software, with the consideration of low temperature and the action of load coupling; reasonable stress absorbed layer parameters are determined.Two kinds of evaluation indexes--- the deflection value of asphalt concrete pavement and bottom tensile stress at base level are considered; ABAQUS finite element analysis is respectively conducted on rubber asphalt stress absorbed layers at light, medium and heavy-duty transportation; the deflection value of pavement structure and tensile stress at the bottom of semi-rigid base layer in different combinations of the thickness of rubber asphalt stress absorbing layer and semi-rigid base are obtained by using ABAQUS software,the optimization scheme of pavement structure with light, medium and heavy rubber asphalt stress absorbing layers is recommend.Through the above research, it is hoped the research results can bring certain economic benefits and social benefits in the process of practice and provide some suggestions for the crack control of asphalt concrete pavement and pavement maintenance.