Impedance-based structural health monitoring applied to steel fiber-reinforced concrete structures

The goal of the present contribution is to test the effectiveness of an impedance-based structural health monitoring (ISHM) methodology to detect damage in steel fiber-reinforced concrete structures. For this aim, a piezoceramic sensor coated with epoxy is used. A prismatic concrete specimen was evaluated for the case in which the damage condition was obtained from compression testing. The impedance signatures were measured both before and after the compression testing for the specimens placed inside an environmental chamber. An optimization procedure was applied to compensate for the temperature effects that appear on the impedance signatures. For illustration purposes, the coated piezoelectric transducer was initially bonded to the surface of an aluminum beam to detect damage induced by a loosening bolt. An impedance analyzer was used to measure impedance signatures in the frequency range of 40–70 kHz for the procedure with the aluminum beam and 50–80 kHz for the prismatic steel fiber concrete specimen. An in-house portable impedance meter (SySHM impedance meter) was used to measure the impedance signatures. The results encourage the use of the ISHM approach for health monitoring of steel fiber-reinforced concrete structures.