Optical Fiber Sensor for Corrosion Detection and Evolution Monitoring in Reinforced Concrete Structures

Corrosion of reinforced bars (rebars) in concrete structures is a major issue in civil engineering structures, being its detection and evolution measurement a challenge for applied research. In this project we present a new methodology to detect corrosion and its evolution monitoring, based on the direct rebar–concrete interface changes measurement by the use of Optical Fiber Sensor (OFS) either a Fiber Bragg Grating (FBG) network or Optical Frequency Domain Reflectometry (OFDR) interrogation technique providing distributed strain measurement. A built-in pre-strain profile makes possible the detection of general and pitting corrosion with the same sensor. Accelerated corrosion tests were performed in an electrolytic solution under both pitting and general corrosion. A clear correlation is observed between the evolution of the spectral shift and the corrosion progress thus demonstrating the feasibility of this technique.