Research On Viscoelastic Dynamic Response Of Asphalt Pavement With Imperfect Interface Bonding Condition

At present,the design methods of asphalt pavements in domestic and foreign countries are based on the theory of layered linear elastic system with complete continuous contact between layers.However,the design calculation of asphalt pavement structure based on this method,on the one hand,it is difficult to reflect asphalt mixture’s viscoelastic behavior such as the creep and relaxation;on the other hand,interface of asphalt pavement layer is not always continuously,which will cause differences between the calculation results of the mechanical properties of the pavement structure and the actual operating state of the pavement.In view of the above problems,in order to further improve the calculation theory of asphalt pavement structure design,this paper has carried out the research on the dynamic response of imperfect interface asphalt pavement between layers based on the analytical method.The specific content is as follows:First,the modified Burgers model was used to describe the viscoelastic deformation characteristics of the asphalt mixture in the form of complex modulus,considering the actual contact conditions of the pavement structure,and a calculation model for imperfect interface asphalt pavement between layers under vehicle load was established.We used Hankel-Laplace transformation to transform the dynamic balance partial differential equations into ordinary differential equations,constructed the transfer matrix of the relationship between the displacement and stress of each layer of the pavement,introduced the transformation matrix to change the continuity state between the layers,and obtained analytical solution of dynamic response of imperfect interface pavement structure between layers according to boundary conditions.Based on the calculation results of the example,it is found that the viscoelastic coefficient B andη₂ of the asphalt mixture has a certain delay effect on the time when the peak deflection of the road surface appeared under the action of the vehicle load,and the imperfect interface condition of the pavement structure will make the road surface deflection response significantly increased.Secondly,considering the braking situation of the vehicle,the horizontal load and vertical load when the vehicle is braking are respectively simplified into continuous semi-rectangular wave and semi-sine wave,and the analytical expressions of the dynamic response of imperfect interface asphalt pavement between layers under the vehicle braking condition was derived.The research showed that the road surface deflection response under vehicle braking conditions is stronger than when horizontal loads are not considered and the good interlayer bonding condition is an important way to improve the road surface deflection response.In the end,considering the effects of interlayer adhesion coefficient,surface layer thickness,base layer thickness,base layer modulus,soil base modulus,surface layer elastic modulus and viscoelastic coefficient,the orthogonal experiment was designed.Through the orthogonal visual range analysis method,the sensitivity of each influencing factor to the response of asphalt pavement surface deflection was analyzed.The results showed that the primary factor affecting road surface deflection is the interlayer adhesion coefficient.In this paper,the analytical expressions of the dynamic response of imperfect interface asphalt pavement between layers were obtained by the analytical method,and the calculation program was compiled to study the dynamic response of the asphalt pavement more deeply.This result has a certain impetus to the calculation theory of asphalt pavement structure,and can provide a certain reference for the optimization and design of pavement structure.