Acoustic parameter analysis of CFRP-reinforced concrete with different bonding interfaces

Carbon fiber reinforced polymer (CFRP) is widely used for reinforcing concrete structures, with the bond quality between CFRP and concrete being crucial for effective reinforcement. Early detection of delamination between CFRP and concrete is essential for structural safety. This study employs the ultrasonic pulse-echo method to inspect physical models of CFRP-reinforced concrete interfaces with four different debonding sizes. Simulations are conducted to analyze the time-domain and frequency-domain characteristics of pulse echoes at various debonding sizes. Building on these simulations, experiments are conducted to further analyze the acoustic signal characteristics in the time and frequency domains under various inspection configurations, including different excitation frequencies, transducer spacing, and transducer positions relative to the debonded areas. Results show consistency between simulations and experiments: as debonding size increases, acoustic parameters of the echo signal such as maximum amplitude in time-domoin, main frequency amplitude and integrated area in the frequency domain all exhibit significant decreasing trends, with minimal influence from the inspection configurations. This study provides a valuable reference for non-destructive but evaluation of bond quality at CFRP-concrete interfaces.