A time-saving method to determine the chloride threshold level for depassivation of steel in concrete

The chloride threshold level is an essential influence on the service life of concrete structures exposed to chloride environment, hence it is important to develop a time-saving method for its measurement. A low voltage electro osmosis method was developed to accelerate the migration of chloride ion in concrete and to increase chloride content to the threshold level in this work. Both macrocell and microcell current measurements were used to confirm the corrosion initiation status of steel. As a result, the chloride content on surface of the soaked working electrode, which could be obtained within 5 days, was found to be an effective indicator for chloride threshold level.