Effectiveness of impressed current technique to simulate corrosion of steel reinforcement in concrete

Accelerated corrosion by means of the impressed current technique is widely used in concrete durability tests. In this study, the influence of varying the impressed current density level between 100 and 500 muA/cm(2) on the actual degree of steel. reinforcing bar corrosion as well as on the concrete strain behavior due to expansive-corrosion products was experimentally investigated. Twelve reinforced-concrete prisms (150X250X300 mm) were used. The prisms were reinforced by two No. 10 reinforcing bars. Corrosion was induced by means of impressed current using electric power supplies. To depassify the steel reinforcement, 5% NaCl by weight of cement was added to the concrete mix. The strain response due to the expansion of corrosion products was measured at each face of the prisms. At the end of the corrosion phase, all the corroded reinforcing bars were removed, cleaned according to the ASTM G1-90 standard, and weighed to get the actual degree of mass loss. The results showed that, up to 7.27% mass loss, accelerated corrosion using the impressed current technique was effective in inducing corrosion of the steel reinforcement in concrete. With respect to Faraday's law, the use of different current densities has no effect on the percentage of mass loss. However, increasing the level of current density above 200 muA/cm(2) results in a significant increase in the strain response and crack width due to corrosion of the steel reinforcement.