Research On Dynamic Response And Crack Mechanism Of Composite Pavement With Stress Absorbing Layer

A great quantity of research indicated that the composite pavement which adds asphalt concrete upper layer on cement concrete pavement can overcome the shortcomings and concentrate structure advantages of cement concrete pavement and asphalt pavement. But it's susceptible for Asphalt layer to format reflection crack under the effect of external load, because the old cement concrete board existed original joints and crack defects. Setting stress absorbing layer between asphalt layer and cement concrete face can effectively delay and even prevention the production of reflection crack, in view of this, this article calculated the mechanical response and discuss the anti-crack mechanism of setting modified asphalt mixture stress absorbed layer composite pavement.This paper applied the moving sine wave loads to structure and calculated the mechanical characteristics of composite pavement two different structures that one set and one don't set stress absorbing layer using finite element software. Pavement structure mechanical response was contrast Analyzed under static load and dynamic loading and analyzed the influence of pavement roughness on structure stress and the deflection. The results showed that two structures stress and deflection of joint were increased with the decreasing of flatness. On this basis, it contrasted the mechanical response by changing the thickness and modulus of each layer. The calculation found that the stress concentration of juncture place was improved obviously after setting stress absorbing layer. The stress absorbing layer thickness and modulus advisable values were proposed according to the calculated results. In addition, this paper simulated the fracture path and obtains the fatigue life of two different structures that one set and one don't set stress absorbing layer through the Franc2d software. It contrasted the results of the two different structures. It was directly that the fatigue life was improved obviously after adding the stress absorbing layer. Therefore the stress absorbing layer can effectively improve the stress state of pavement structure and can effectively prevent and delay the production of reflection cracks. Thereby this will prolong the fatigue life of pavement structure. At last, on the base of above analysis, this paper discussed the combination design of composite pavement structure and produced the ultimate failure state for pavement structure design.