Diagonal macro-crack induced debonding mechanisms in FRP rehabilitated concrete

The effectiveness of externally bonded fiber reinforced polymer (FRP) composites to strengthen concrete components depends intrinsically on bond and transfer related aspects. Premature debonding, initiated from ends or from cracks in the concrete, often limits potential performance gains. While end initiated debonding and peeling mechanisms have been researched extensively, crack initiated debonding has not been studied to the same extent. This paper investigates mechanisms associated with diagonal cracks and models debonding initiation and propagation through a fracture mechanics based finite element approach. It is seen that debonding propagation is mainly caused by mode II fracture mechanisms and that the interfacial failure path is primarily governed by relationships between concrete cracking behavior and interfacial properties.