Electrochemical Sensors for Monitoring the Corrosion Conditions of Reinforced Concrete Structures: A Review

Several methods for corrosion monitoring of reinforced concrete structures (RCS) have been proposed in the last few decades. These systems may be used either in new, existing or repaired structures. The corrosion monitoring can be performed by different methodologies. These may or may not be destructive, use different degrees of complexity and cost, and provide information on the progression and kinetics of the corrosion phenomena. The destructive methods are limited to sampling. Therefore, these may not be representative of the whole structure, which is extremely important in RCS with large heterogeneities both in terms of materials used and in terms of the exposure environment. Within this context, non-destructive methods have been widely developed, which are intended to provide quick information about the entire structure. Ideally, these systems should be able to detect the corrosion state of the steel inside the concrete, the main causes of corrosion and the evolution of corrosion phenomena over time. This manuscript reviews and summarizes the actual state of the art and the main achievements in the field of electrochemical sensors based on non-destructive methods for corrosion monitoring of RCS in the last few years. The challenges and perspectives in this field will also be discussed.