Damage, nondestructive evaluation and rehabilitation of FRP composite-RC structure: A review

Fiber reinforced polymer (FRP) composites have been widely used to retrofit RC structures, such as with externally bonded FRP laminates (EB), externally bonded reinforcement on grooves (EBROG), embedded FRP bars (embedded), near surface mounted FRP bars/strips (NSM), and mechanical anchorage (MA). Damage to retrofitted structures can be evaluated in advance or in real-time by nondestructive detection techniques (NDTs) to assess the health conditions, whether in the construction stage, service stage, or repair stage. This present work reviews valuable studies on the damage detection of existing FRP composite-RC structures conducted by some well-known NDTs, including piezoelectric transducer (PZT) methods, acoustic emission (AE) monitoring, ultrasonic testing, fiber optics sensor methods, microwave detection, acoustic laser detection, infrared thermography (IR), and digital image correlation (DIC). First, the damage levels of FRP composite-RC structures are presented to determine the inspection objects. Then, the capacities, advantages, and disadvantages of the NDTs are discussed by inspecting the damage levels. Moreover, considering the damage levels, the suggestions for selecting potential NDTs and repair measures are presented for different FRP composite-RC structures. Finally, the research needs in this field are discussed to better develop and apply NDTs for detecting FRP composite-RC structure damage.