Crack development in bonded concrete overlays subjected to differential shrinkage: A parameter study

摘要

The bonded concrete overlay technique is one of the most widely used methods for repair, retrofitting and rehabilitation of concrete structures. Differential shrinkage is commonly the most crucial factor influencing the performance of the composite system and may result in extensive overlay cracking. Based on strain measurements, fundamental characteristics of overlay strain and stress development under restrained conditions were identified. The restraint of overlay deformations was found to depend less on the relative cross-sectional dimensions of substrate and overlay than is commonly assumed. A new analytical approach for the design of bonded overlays subjected to differential shrinkage is introduced, based on localised strain conditions at the interface between substrate and overlay. A parameter study of the most important influences on overlay stress development is performed.