Analysis Of Cement Concrete Pavement Structure With CA Mortar Function Layer

Structural damage such as broken plates,slab staggering and base damage commonly happens in the early life of cement concrete pavement in our country which seriously affecting the performance of cement concrete pavement and greatly shorten the service life of cement concrete pavement.Based on analysis of the current research in our country and abroad,this paper puts forward a solution which is setting up the cement emulsified asphalt mortar(CA mortar)between the cement concrete pavement and the base layer.The purpose is,with the material properties of CA mortar layer,reduce the adverse stress of pavement and the base of and prevent,avoid the formation and destruction of transition layer,protect the base from erosion,thus putting off damage in the life of cement concrete pavement structure.In this paper,the mechanical properties of the new cement concrete pavement structure are analyzed by mechanics,which has important theoretical and practical value.Based on real material properties by means of experimental method conducted on C A mortar function layer,a three-dimensional finite element model of pavement structure was established to study the mechanical properties of CA mortar function layer of cement concrete pavement structure.The main research work and conclusions are as follows:First of all,currently research status of contact state between pavement and base of cement concrete pavement interlayer in our country and abroad are summarized and analyzed which shows setting up a function layer between pavement and base research has shown that in the cement concrete surface layer and the base layer is an effective method to improve the contact condition between pavement and base.This paper also summarized several common material used for function layer and analyzed their advantages and disadvantages then put forward the solution which is setting up a CA mortar function layer between concrete pavement and base.Secondly,on the basis of previous research,3 CA mortar mix designs with different constituent ratio were tentatively mixed for determination of the indexes of physical and mechanical properties,then one of them with best performance was selected;Burgers model is selected as the viscoelastic constitutive relation model,then creep test was done to attain the four parameters of Burgers model,and transformed the four parameters into viscoelastic material parameters under the Prony series of ABAQUS by Laplasse transform,and the correctness of the CA mortar viscoelastic model is verified by finite element method.Thirdly,establish the model of pavement structure under static load and analyze the changes of vertical movement and stress of pavement strcture under load caused by adding CA mortar function layer into the pavement structure,and conclude the function of CA mortar layer;analyze the influence on structural mechanics performance of cement concrete pavement with CA mortar layer caused by changes of parameters,based on the results of the analysis,put forward some reasonable suggestions about main parameters of the pavement structure layer,in particular,reasonable thickness of function layer for different types of base.Finally,establish the model of pavement structure under moving load,for semi-rigid or rigid base of pavement structure with and without CA mortar layer,analyze fluctuations and movements of maximum deflection value,maximum compressive stress of pavement and base,maximum tensile stress of bottom and maximum tensile stress at horizontal direction.Find out the rules of above fluctuations and movements,then analyze the function of CA mortar layer by comparing the peak vales.The results show that:the vertical movement,compressive stress of pavement and base,maximum tensile stress of bottom and tensile stress at horizontal direction of cement concrete pavement structure are reduced by adding CA mortar layer.Through comparison and analysis,it is proved that CA mortar can improve the performance of cement concrete pavement.The research results are valuable for engineering application of the cement concrete pavement structure,which can provide reference for the application of CA mortar functional layer in cement concrete pavement structure.