Identification of bond behavior between FRP/steel bars and self-compacting concrete using piezoceramic transducers based on wavelet energy analysis

The civil infrastructures constructed using self-compacting concrete (SCC) reinforced with fiber-reinforced polymer (FRP) bars are advocated for engineering applications due to corrosion resistance and environmental-friendly performance. The bond behavior between FRP reinforcement and SCC is a significant factor affecting the serviceability and failure mechanism of this composite structure. However, it is hard to identify the damage mechanism and failure mode of the interface bond using the traditional test methods. Therefore, an effective monitoring method of interface damage using piezoceramic transducers is proposed in this paper. A series of pull-out tests were performed, and the test variables involved concrete materials and reinforcing bar types. A lead zirconate titanate (PZT) patch transducer acting as an actuator was bonded on the outer surface of reinforcing bars, and a piezoceramic smart aggregate transducer acting as a sensor was embedded in the SCC. A wavelet energy ratio index (WERI) is proposed to identify the damage mechanism of interface between reinforcing bars and SCC. The experimental test results reveal that the damage mechanism and failure mode of the bond between different reinforcing bars and concrete materials can be identified effectively and the peak of bond stress can be captured accurately by using WERI values.