Monitoring of chloride-induced corrosion in steel rebars

Chloride-induced corrosion is very serious for steel rebar, because chloride-induced corrosion causes local disruption in the passive layer of the steel, forming surface pits. This paper proposes a novel corrosion monitoring method for steel rebars on the basis of the stress concentration in the plane stress condition caused by chloride-induced corrosion. The fundamentals of corrosion monitoring and the design concept of the proposed sensor are illustrated. The influence factors for corrosion monitoring are simulated to improve the sensitivity. Potentiostatic accelerated corrosion tests are conducted to evaluate the efficacy. The studies indicate that this indirect method for monitoring changes of physical properties caused by corrosion is effective. Influence factors in chloride-induced corrosion can be neglected, as compared with electrochemical techniques. The proposed corrosion monitoring method can provide useful information to evaluate the risk of corrosion initiation and propagation for steel rebars.