Mechanical Response Analysis Of Tramsverse Crack Treatment Of Asphalt Pavement Based On Discrete Element Method

Transverse crack is one of the most common damage of asphalt pavement,which has a serious influence on the function and structure life of road,so how to treat transverse cracks is an important subject.Especially,the treatment of severe transverse cracks has become a technical difficulty.There are some problems in the treatment of severe transverse cracks in asphalt pavement,such as imperfect technology and random use of materials,which lead the treatment of cracks easy to damage.Based on this,this paper studies the influence of cutting geometric structure and repairing material modulus on transverse crack treatment by using discrete elements which can simulate the discreteness and non-uniformoty of pavement materials,and puts forward the suitable cutting geometrical structure and the modulus ratio of repairing material to the old pavement,which provides the basis for the treatment of transverse cracks in asphalt pavement.Firstly,a two-dimensional discrete element model of asphalt mixture was established,and the microscopic parameters in the discrete element model of asphalt mixture were obtained.Based on reasonable assumption,the asphalt mixture is simplified into a combination of voids,coarse aggregates and asphalt mortar.The two-dimensional discrete element model of asphalt mixture was established by using PFC software.The linear model was selected as the contact model between coarse aggregate particles,and the contact between the other particles was in the form of a Burgers contact model combined with the maximum adhesion force.The microscopic parameters of asphalt mixture were obtained by laboratory tests of asphalt mortar and mixture.The assignment of contact parameters and the procedure of applying maximum adhesion between particles were completed by using FISH language.The reliability of the modeling method and the microscopic parameters was verified by the discrete element simulation of the laboratory tests of the asphalt mixture.Then,the mechanical response of transverse cracks treatment in different cutting geometrical structures under wheel load and temperature load was analyzed,and some suggestions on the geometrical structure of groove in the treatment of transverse cracks were put forward.Based on the orthogonal idea,the stress or deformation of the groove wall,the junction of groove wall and the repairing material,and the bottom of the repairing material were selected as indexes.The influence law of the cutting geometric structures factors on each index was analyzed when the wheel through the crack treatment.The suitable cutting geometrical structure for the transverse crack treatment under the wheel load was put forward.And the analysis results were confirmed by laboratory test.Using the method of orthogonal test,taking the displacement of groove wall when the low temperature crack appears and crack propagation time as indexes,the influence of geometric structures factors on indexes when the groove wall is stretched the repairing material because of cooling was analyzed.Taking the maximum shear stress and maximum principal stress inside the repairing material as indexes,the influence law of geometric structures factors on indexes was analyzed when the groove wall squeezes the repairing material as a result of heating up.Combined with the response law of crack treatment under wheel load and temperature load,some suggestions were put forward for the cutting geometrical structure of transverse crack treatment in asphalt pavement.Finally,several suitable cutting shapes were selected,and the influence of the repairing material's modulus on the mechanical response of transverse cracks in asphalt pavement under wheel load was analyzed.And the conclusion that when the modulus ratio of repairing material to the old pavement is 0.14~1.76,the durability of the crack treatment is good was obtained.