Feasibility study on corrosion monitoring of a concrete column with central rebar using BOTDR

Abstract

Abstract. Optical fiber Brillouin sensor in a coil winding setup is proposed in this paper to measure the expansion deformation of a concrete column with a central rebar subjected to accelerated corrosion. The optical sensor monitored the whole dynamic corrosion process from initial deformation to final cracking. Experimental results show that Brillouin Optical Time Domain Reflectometer (BOTDR) can accurately measure the strain values and identify the crack locations of the simulated reinforced concrete (RC) column. A theoretical model is used to calculate the RC corrosion expansive pressure and crack length. The results indicate that the measured strain and cracking history revealed the development of the steel bar corrosion inside the simulated RC column. Keywords: rebar corrosion; expansion pressure; BOTDR; optical fiber; distributed sensing monitoring 1. Introduction Steel corrosion is one of the predominant factors for the degradation of steel reinforced concrete (RC) structures especially for structures exposed to aggressive environments. Corrosion of steel rebar is considered negligible when it is fully surrounded by the alkaline environment of concrete. However, corrosion can be introduced during penetration of chloride ions and carbon dioxide. To quantify the rate of corrosion, electro-chemical methods such as corrosion potential, AC impedance, half-cell and linear polarization methods have been suggested (Andrade