MONITORING THE CORROSION OF REINFORCING STEEL

Abstract

This article describes some equipment and techniques used for monitoring the corrosion of reinforcing steel in concrete structures. A list of devices currently available with their uses and recording methods is provided together with a short description of the theory of each type of device. Some probes are still undergoing evaluation. These are the following: the linear polarization, corrosimeter, sereda, and beeby corrosion probes. The method by which these probes can be integrated to form a corrosion monitoring station is also described. Brief details of two portable corrosion monitoring devices, the potential wheel and the taywood resistivity meter, and also provided. The potential wheel is effectively a half cell with a wheel for a tip. Placing the wheel in contact with the concrete sample, it may be drawn rapidly across the surface to provide a continuous read-out of the corrosion potential. The taywood resistivity meter (four probe method) measures resistivity in situ. The four probes of the handheld resistivity probe and spaced equal distances apart and placed in electrical contact with the concrete surface. A current is passed between the outer current probes and a voltage difference is measured across the inner voltage probes. The resistance can then be calculated using these measurements.