Sensors for Monitoring Corrosion of Steel Embedded in Concrete

Abstract

This paper presents the use of an innovative low cost sensor for monitoring corrosion of steel members embedded in concrete. Corrosion of steel reinforcing bars or embedded steel in concrete structural components is a major concern for structures such as bridges and parking garages. Moisture and chloride ingress through the cracks is the primary reason for corrosion of such concrete structures. The chloride and moisture levels significantly affect the electrical conductivity of concrete. A low cost sensor for measuring concrete resistivity (or conductivity) was developed by researchers at West Virginia University. This sensor is very durable and can be embedded in concrete members (beams, columns, etc.) at the time of pouring concrete. The electrical resistivity measurement obtained using this sensor can be used to evaluate the potential for corrosion of embedded steel. This paper presents laboratory and field results obtained using the sensor to demonstrate its usefulness. The paper also highlights the simplicity and ease of use of this sensor. In addition, the paper also discusses the use of a commercially available temperature/humidity sensor that can be used in conjunction with the electrical resistivity sensor for a comprehensive assessment of the potential for corrosion of steel embedded in concrete.