Combined Effect of Tire Contact Pressure and Longitudinal Grade on the Interface Shear Stress of HMA Overlay over Ballast Concrete

Guangming Wang, Ph.D, PE
Dennis Morian, PE
Doug Frith, PE
Hao Wang, Ph.D
Transportation Research Board 93rd Annual Meeting
Interface Shear Stress; HMA; Overlay; Contact Pressure; Finite Element


In this study, a sophisticated three-dimensional (3-D) finite element model was developed to investigate the effects of temperature, overlay thickness, non-uniform contact stress, longitudinal grades, and loading time on responses of the interface shear stress. The results indicate that increasing the asphalt overlay thickness will significantly reduce the interface shear stress. Increasing temperatures will slightly increase the interface shear stress. Non-uniform contact pressure will cause more interface shear stress than uniform contact pressure. Increasing the longitudinal grade will increase the interface shear stress. Further, the interface shear stress will increase with the loading time when the asphalt mixture is treated as a viscoelastic material. The study provides insights on how to determine the interface bond strength for overlays when the design is subjected to complicated loading and geometry conditions.