Debonding detection in CFRP-retrofitted reinforced concrete structures using nonlinear Rayleigh wave

This paper proposes the use of nonlinear Rayleigh wave to inspect debonding in carbon fibre reinforced polymer (CFRP) retrofitted reinforced concrete structures. The proposed method requires a network of transducers that are used to scan the CFRP-retrofitted reinforced concrete structures by sequentially actuating and receiving Rayleigh wave. The nonlinear feature used for the debonding detection is second harmonic generation due to the interaction of Rayleigh wave at the debonding between the CFRP and concrete interfaces. A damage image reconstruction algorithm is proposed to provide a graphical representation for detecting and locating the debonding in the CFRP-retrofitted reinforced concrete structures. In this study, experimental case studies are used to demonstrate the performance of the proposed debonding detection technique. A transducer network with four piezoelectric transducers is used to actuate Rayleigh wave and measure the second harmonic in the experiments. The results show that the proposed debonding detection technique is reliable in detecting and locating the debonding in the CFRP-retrofitted reinforced concrete structures.