Debonding mechanism of bonded concrete overlay according to horizontal traffic loading

Abstract

Recently, bonded concrete overlay has been considered as a possible alternative material for use in pavement rehabilitation as its material properties are similar to those of the existing concrete pavements. In a bonded concrete overlaid pavement, both the overlay layer and the existing pavement should perform as one monolithic pavement and bonding between the overlay layer and the existing pavement is essential. Therefore, bonded concrete overlays are carefully constructed to achieve and maintain the bond between the overlay layer and the existing concrete pavement using milling, blasting method and bonding agent. Generally, typical debonding failure modes of bonded concrete overlay observed in the loss of bonding, failure by normal tensile stresses, and horizontal shear stresses. Previous study indicated that normal tensile stress at the interface is main cause of debonding in bonded concrete overlay. However, the bonded concrete overlay at the traffic congested section and toll booth of expressway experience due to stopping and starting of vehicle. This may lead to debonding by horizontal shear stress at the interface of bonded concrete overlay. This study aimed to investigate the debonding mechanism of bonded concrete overlay due to horizontal shear stress. A set of numerical analysis was performed in order to evaluate the horizontal shear stress at the interface of bonded concrete overlay due to vehicle stopping and starting of vehicle in the traffic congested section and toll booth of expressway.