A Study on Monitoring the Curing Process of Structural Adhesives Using Wave Propagation

Structural adhesive can be used to bond fibre-reinforced polymer (FRP) composites onto existing structures for strengthening and retrofitting purposes. Monitoring the curing process of the adhesive is desirable in order to confirm the strength and integrity between the FRP and the structure. This paper reports the application of the wave propagation (WP) technique, employing Lead Zirconate Titanate (PZT) transducers, for monitoring the curing process of structural adhesives. The wave velocities of solidwaves propagating across adhesive samples were experimentally measured throughout the curing process. Results show that the wave velocities increased rapidly in the first 24 h. However, the rate of increase declined significantly thereafter. Ultimately, this study successfully demonstrates the capability of theWP technique for monitoring the curing of structural adhesives.