Effect of high temperature on nonlinear guided wave in reinforced concrete structures

Abstract

There are some ations that reinforced concrete (RC) structures may be subjected high temperatures, e.g., building fires, rocket and jet aircraft engine blasts, and nuclear power reactors. It is crucial to ensure the integrity and safety of these RC structures. This study investigates the effects of high temperature on the behavior of nonlinear guided wave, which can potentially be used for non-destructive evaluation, in reinforced concrete structures. In this study, the reinforced concrete specimens are heated from 100 to 800°C. Two sets of experimental studies are considered. At temperatures 100–300°C, piezoceramic transducers are embedded at the rebars in the reinforced concrete specimens to generate and measure the longitudinal wave. At temperatures 300–800°C, the longitudinal transducers are installed at the rebars exposed outside the reinforced concrete specimens. The results show that the high temperature induces the debonding between the rebar and the concrete, which causes the generation of the second harmonic when the longitudinal wave interacts with the debonding. A nonlinear parameter is defined to monitor the effects of the heat damage caused by the increasing temperature on the reinforced concrete structures.