A Novel Optical Fiber Sensor for Steel Corrosion in Concrete Structures

Abstract

Steel corrosion resulting from the penetration of chloride ions or carbon dioxide is a major cause of degradation for reinforced concrete structures,. The objective of the present investigation was to develop a low-cost sensor for steel corrosion, which is based on a very simple physical principle. The flat end of a cut optical fiber is coated with an iron thin film using the ion sputtering technique. Light is then sent into a fiber embedded in concrete and the reflected signal is monitored. Initially, most of the light is reflected by the iron layer. When corrosion occurs to remove the iron layer, a significant portion of the light power will leave the fiber at its exposed end, and the reflected power is greatly reduced. Monitoring of the reflected signal is hence an effective way to assess if the concrete environment at the location of the fiber tip may induce steel corrosion or not. In this paper, first the principle of the corrosion sensor and its fabrication are described. The sensing principle is then verified by experimental results. Sensor packaging for practical installation will be presented and the performance of the packaged sensors is assessed by additional experiments.

Monitoring Concrete Deterioration Due to Reinforcement Corrosion by Integrating Acoustic Emission and FBG Strain Measurements

“…McCague et al designed a novel corrosion sensor based on birefringent photonic crystal fibers for pressure/force measurement [26]. Leung et al proposed a steel corrosion detection method using a simple light reflection technique, in which one end of the fiber was coated with an iron thin film to interrogate steel corrosion [27]. Li et al devised a metal loss detector for corrosion measurement based on fiber optic macro-bend light loss [28].…”

Evaluation of Concrete Corrosion using EMI Sensor

“…However, to overcome the problem associated with destructive methods of testing the RC for corrosion many non-destructive evaluation techniques have evolved in recent years due to as technological advancement. Few method performed by different researcher are as follows: open circuit potential (OCP) monitoring is called as electrochemical methods [4], electromagnetic (EM) methods (i.e., ground penetrating radar (GPR)) [5], elastic wave methods (i.e., ultrasonic pulse velocity (UPV) [6], galvanostatic pulse method (GPM) [7], electrochemical noise (EN)) [8], resistivity method [9], polarization resistance [10], optical sensing methods (i.e., fiber Bragg grating (FBG)) [11], acoustic emission (AE) [12], impact echo (IE)) [13], infrared thermography (IRT) and most common methods used is visual inspection [14]. Whereas common methods used for monitoring in RC structures are visual inspection, polarization resistance, OCP, and other electrochemical methods.…”

Real‐time monitoring of the degradation of metallic and organic coatings using electrical resistance sensors

“…In contrast to a wide range of products for corrosion monitoring in aqueous media, the availability of means for real‐time corrosion monitoring in the atmosphere is limited, especially in aggressive environments. The available methods used in the literature are either not adapted for such corrosiveness, such as quartz crystal microbalance, or limited to model materials, such as methods based on optical fibers or radio‐frequency sensors . Even if the ultrasonic methods allow reaching the micrometer scale, in terms of corrosion depth through complex modeling, it is usually limited to single material of millimetric thickness .…”