The influence of reinforcement steel surface condition on initiation of chloride induced corrosion

This paper describes a part of the work in the development of a “standard” test method for determining chloride threshold values required to initiate corrosion on reinforcement in concrete. The prerequisites of the test set-up are that the test conditions should be reasonably comparable to those in service and the test method should be fairly reproducible and as rapid as possible concerning the slow diffusion nature of the investigated phenomenon. This paper presents the results from a study on the influence of steel bar surface condition on chloride induced corrosion. Various electrochemical techniques were employed in the study to monitor the corrosion behaviour of the embedded bars with three different surface conditions. It is shown that the steel surface condition has a strong effect on the corrosion initiation of reinforcement in concrete, and can likely be the most decisive parameter attributing to the variability in the reported chloride threshold values.