Analysis of in situ bond strength of bonded concrete overlay

Cement concrete pavement has become a popular candidate for highway construction in Korea because it is capable of withstand the heavy vehicle traffic. The service life of some highways is close to the end and they require the rehabilitation to extend the service life. Therefore, bonded concrete overlay is a good alternative, since its material properties are similar to the existing concrete pavement. However, it is recently reported that the early distresses occur in bonded concrete overlay and poor bonding between the overlay and the existing pavement is assumed to be the cause of this problem. According to the pre-investigation result in laboratory, there are two factors causing the poor bonding: the concrete overlay types and the substrate condition. The study investigates the vulnerable factor among the two factors based on the analysis of in situ bond strength data of bonded concrete overlay collected from some highways in Korea. As a result, the substrate condition becomes a vulnerable factor influencing the poor bonding and causing the early distress in bonded concrete overlay.