Design of a long-period fiber grating sensor for reinforcing bar corrosion in concrete

In this article, a fiber monitoring technique for detecting the state of rebar corrosion in concrete is proposed, which uses the sensitivity of the long-period fiber grating (LPFG). In this technique, the configuration of a LPFG rebar corrosion sensor is carefully designed to detect the changes of refractive index around rebar in concrete caused by chloride and liquid rust. In the experiment, the sensor using the corresponding package was embedded in concrete structures. The LPFG spectrum curves corresponding to different refractive indexes of the environment under test were captured by the monitoring technique of LPFG transmission spectra, and the relationship between the resonance peak wavelength and the state of rebar corrosion in concrete was obtained. The experimental results numerically showed that the sensor response has good regularity for a wide range of travel.