Localized Debonding as a Potential Mechanism for Near-Surface Cracking

Research on the potential link between debonding and cracking has primarily focused on changes in location and magnitude of maximum tensile stress/strain under the load center for various interface bonding conditions. Prior modeling efforts have evaluated smeared bonding conditions, which represented the entire interface as either bonded, partially bonded or debonded. However, field evidence indicates debonding is a local phenomenon that starts at a critical location and gradually progresses through a portion of the interface. A parametric study identified a critical zone of high shear stress coupled with low confinement where the onset of debonding is likely. This critical zone is located around the mid-depth of the asphalt layer and extends for nearly 5 cm from the edge of the tire. Localized debonding should be introduced at the identified critical zone to better evaluate stress redistribution resulting from interface failure. Localized debonding was shown to potentially lead to stress states of shear-induced tension in the portion of the interface near the tire edge, which can explain the initiation of near-surface longitudinal cracking.