Deflection Criterion at the Joint of Existing JPCP Pavement Overlayed with HMA

Abstract:

When hot mixture asphalt(HMA) is used to remedy functional or structural deficiencies of existing joint plain concrete pavement(JPCP),reflection cracking is a major distress mode in HMA overlay.The basic mechanism of reflection cracking is the propagation of cracks through the overlay due to deflection difference at the joints vicinity of the existing pavements.The model of JPCP was created by three finite element method and the relationship between joint deflection difference and effects such as base modulus,elastic coefficient of spring elements was discussed.Based on the model of JPCP,the finite element model of asphalt overlay was created then and shear stress concentration phenomenon was founded at the bottom of HMA where was just above the joint of JPCP.So,the rule of the shear stress at the bottom of HMA with deflection difference was studied.According to Coulomb strength theory and shear fatigue equation of asphalt concrete,the criterion of deflection difference of existing JPCP was put forward by the method that allowable shear stress was less than ultimate strength.The criterion can provide reference for evaluating the transfer ability of JPCP when the asphalt concrete over JPCP is adopted.