Coupled application of innovative electromagnetic sensors and digital image correlation technique to monitor corrosion process of reinforced bars in concrete

Corrosion monitoring of reinforcement is of great importance in evaluating the durability performance of concrete structures, especially under harsh environments. This paper presents a creative approach that combine using innovative electromagnetic monitoring apparatus (EMMA) and digital image correlation (DIC) technique in order to monitor the reinforcement corrosion inside concrete. The new-type electromagnetic sensor is capable of evaluating the corrosion degree of reinforced bars in concrete, meanwhile, DIC technique is always used to detect the tiny corrosion-triggered deformation on concrete surface. The result shows that joint use of these two techniques can monitor the entire process from corrosion initiation to further corrosion-induced strain variation on the surface of concrete. Besides, concrete beam with higher vertical load level leads to greater bending movement, which will accelerate the corrosion behavior and limit the horizontal strain. Moreover, the characteristics of DIC technique and strain gauges are compared respectively.