Innovative Sensors for Monitoring the Corrosion of Steel Embedded in Concrete Structural Components

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 steel embedded in concrete structural components is a major concern for structures such as bridges and parking garages. Moisture ingress through the cracks is the primary reason for corrosion of such concrete structures, and the problem is compounded with the use of deicing salt in winter months. The salt and moisture levels significantly affect the 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 data from the sensor can be used to infer the moisture and chloride ingress during the structure’s service life, and this information is useful in evaluating the potential for corrosion of embedded steel. This paper presents laboratory and field results obtained using the resistivity sensor to demonstrate its usefulness. The paper also highlights the simplicity and ease of use of this sensor. In addition, the paper demonstrates the use of commercially available temperature/humidity sensor which can be used in conjunction with the concrete resistivity sensor. Finally, the field results obtained after installing the sensors during a bridge rehabilitation work in East Lynn, West Virginia, indicate that there is no corrosion activity in the steel pile encased in concrete during the first year following the structural rehabilitation.