A Mechanism Research On The Fracture Failure Of Cement Concrete Pavement Slabs Under Different Supporting Conditions

Cement concrete pavement slabs has lots of advantages,such as high strength, good stability,good durability,long life,low maintenance cost,However,in practical application,because of differences in the settlement and other reasons for the slabs caused local void and boundary conditions change,lead to the stress concentration phenomenon,coupled with the repeated loading of vehicles,cement concrete slabs easily cause the fracture.There are three main issues to solve concrete slab fracture: the settlement which was occurred after construction completed lead to boundary conditions change and stress distribution of cement slabs;the force and deformation of the cement concrete pavement slabs under different supporting conditions;the mechanism on the fracture failure of cement concrete pavement slabs in the elastic supporting conditions.The paper has done some research work about this issue;the main contents of paper are as follows:1,It was introduced and analyzed the reasons of void,fracture type,fracture criterion,fracture mechanism,calculation of fatigue life of cement concrete pavement.Specifically for cement concrete pavement at state of vertical void,derived the isogram of flexural tensile stress(σ_x)with uniaxial and biaxial set at change of void size;derived the diagram of flexural tensile stress with the effect of critical load site at change of slab thickness;derived the diagram of max flexural tensile stress with uniaxial set at change of critical load site and flexural tensile stress(σ_x) with the effect of overload.2,It was introduced the several model of cement concrete pavement slab's joint pole.Use three-dimensional finite element program,the different of void size,shape, position,thickness,load levels,communication ability and other factors was analyzed, and summarized some of the relevant Law.3,Some related experimental about fracture failure of Cement concrete slabs under different supporting conditions has done.And summarize the impact of the vertical viod,horizontal viod,corner viod and cycle load about fracture features, some relevant calculation formula has get.