Abstract
It has been proven that the interface bonding between asphalt layers is critical to flexible pavement performance, especially for pavement overlays. However, the requirement on interface bonding strength has not been specified to prevent premature pavement failure, such as slippage cracking or early fatigue cracking. In this paper, pavement structural analysis was conducted to predict the interface shear stress between the surface and intermediate asphalt layers under the combination of vertical and horizontal loading at different temperatures. The effect of interface debonding on pavement life was quantified using the state-of-art mechanistic-empirical pavement-analysis software (AASHTO Pavement-ME) with local parameters. Field cores were taken to measure the interface bonding strength; using the direct shear device theoretical analysis, results show that the minimum-bond-strength requirement should be around 70 psi to prevent premature pavement failure, such as slippage cracking or fatigue cracking. This requirement can be easily achieved in field projects based on the testing results of bond strength from field cores.