Wireless Corrosion Sensors for Reinforced Concrete Structures

Corrosion of embedded reinforcing steel and the resulting deterioration of concrete structures is a worldwide problem. As part of a health monitoring scheme for reinforced concrete structures, early detection of corrosion would allow remedial or preventative measures before structural damage occurs. Embedded wireless corrosion sensors that are successful in detecting threshold amounts of corrosion have been developed and tested. The sensors consist of sealed circuits with exposed steel sensing wires for direct detection of corrosion. Batteries are not necessary for the sensor because power and communication are achieved through inductive coupling with an external transmitter/receiver. The low-cost sensors are fabricated from inexpensive and readily available materials, and require no maintenance. Corrosion is detected by measuring the impedance response of the sensor. An automated signal processing routine can be used to evaluate the measured response and detect if a threshold amount of corrosion has occurred.