Chapter 17 - Advances in corrosion monitoring of reinforced concrete using active and passive sensing approaches

Abstract

The information and communication technology-driven smart cities make the lives of city dwellers safe and convenient. Recently, sustainable reinforced concrete (RC) structures that last longer have become a matter of considerable interest. RC structures are subjected to various damage such as corrosion, debonding, and concrete degradation. The corrosion of reinforcement steel bars (rebars) poses a significant threat to the aging infrastructure, and researchers are seeking methods for its real-time monitoring. The primary cause of corrosion is the ingress of chloride ions into the concrete due to environmental conditions. The changes in electrochemical characteristics of the structures are measured by methods such as half-cell potential, concrete resistivity, and galvanostatic pulse for corrosion detection. Few other methods use the changes in the mechanical response of the structures to detect damage. The conventional periodic inspections require a considerable number of resources and time. Structural health monitoring (SHM) of infrastructure using the permanently installed sensors is a perfect solution to overcome the limitations of conventional methods. There are two types of sensing approaches that can be used in SHM: first, active monitoring such as ultrasonic guided wave-based monitoring, and second, passive monitoring such as acoustic emissions. This chapter discusses the process of corrosion in RC structures and various methods for corrosion detection. Current advances in the sensors, numerical modeling, experimental testing, and signal processing for the detection of corrosion in its embryonic stage are discussed in detail.