Cathodic Protection of Steel Embedded in Porous Concrete

Abstract

The feasibility of applying cathodic protection to carbon steel strands embedded inporous concrete exposed to a chloride-containing environment was investigated. In-situ polarisation experiments were conducted on the embedded steel using a current-interrupt technique. This enabled the magnitude of the iR drop to be determined, and the actual (or corrected) potential of the embedded steel to be monitored throughout the experiments. The results suggested that, for the porous concretes which were examined, the minimum cathodic potential required to protect the embedded steel depended on the concentration of chlorides in the environment. These potentials are −260 mV SHE (−578 mV CSE) for a 0·02 M NaCl environment and −410 mV SHE (−728 mV CSE)for 0·7 M NaCl or sea water solutions.