Investigating the use of equivalent elastic approach to identify the potential location of bending-induced interface debonding under a moving load

Abstract

Poor interface bonding conditions reduce the bearing capacity of asphalt pavements and lead to several distresses. In particular, the association between localized interface debonding and near-surface longitudinal cracking was detected by field observations in the United States. Prediction of potential location and extent of localized interface debonding is important to preclude near-surface cracking. However, there is limited information regarding the onset of localized interface debonding induced by bending. Since interface debonding location and extent may depend on pavement structure, material properties, and loading conditions, a practical approach is needed. Several researchers adopted an equivalent elastic approach to overcome the complexity of modeling the viscoelastic responses of asphalt when evaluating the impact of multiple factors. Therefore, this study focused on determining whether the equivalent elastic approach can be used to identify the potential location of bending-induced localized interface debonding without a significant loss of accuracy. The viscoelastic and equivalent elastic analyses were conducted using 3-D finite element models developed to simulate an asphalt pavement subjected to a moving load. The 3-D equivalent elastic analysis appeared to be sufficient to accurately determine the potential location and extent of localized debonding induced by bending, which are mainly controlled by presence of shear stress in combination with low confinement on the horizontal interface plane. Furthermore, localized debonding was found to likely occur along a strip in the longitudinal direction which resembles a plane-strain problem. This study substantiated that future research efforts can focus on the transverse cross-section when assessing the impact of localized debonding.