Nondestructive Techniques to Investigate Corrosion Status in Concrete Structures

Abstract

A critical step in selecting the most appropriate repair strategy for a distressed concrete structure is to determine the corrosion status of reinforcing bars. Because of the complexity of the corrosion process, it is prudent to involve personnel who are experienced in the corrosion of steel in concrete. The corrosion engineer may employ a variety of tools to help make an assessment of the corrosion conditions. This paper provides an overview of the corrosion of steel in concrete and presents some nondestructive electrochemical tools that are commonly used in corrosion investigations. The objective is to provide the repair specialist with basic information to allow effective communication with the corrosion engineer. Electrochemical principles involved in the corrosion of steel in concrete are reviewed. Subsequently, the half-cell potential method, the concrete resistivity test, and the linear polarization method are discussed. The principles of operation and the inherent limitations of these methods are emphasized.