Durability control of sea-sand concrete components utilizing strong electric field during early curing period

Abstract

Electrochemical chloride extraction (ECE) technology can effectively reduce the harmful chloride ion content of concrete structures and thus decrease their durability failure risk. This paper applied the ECE technology to sea-sand concrete with an excessive chloride ion content through a strong electric field. Further, testing the chloride ion content, meso- and micro-mechanical properties, and mechanical performance of the concrete columns verified their durability performance after the action of the strong electric field. The results show that, for the early-age concrete with a curing period of 3, 5, and 7 days, the strong electric field with an electrifying time of 40, 80, and 120 min can significantly enhance the ECE efficiency, and the chloride ion content of the concrete can fulfill the specification requirements. During the curing period, compared with the unelectrified concrete components, the strain and displacement of the electrified columns increase under the same load when the components are loaded immediately after the action of the strong electric field. However, after applying the electric field, if the member is standardly cured for 28 days, its ultimate bearing capacity increases, and its mechanical properties improve. The bearing capacity of ECEC-3, ECEC-5 and ECEC-7 after curing 28 days are 315.2kN, 320.1kN and 340.9kN which are closed to 326.2kN of ECEC-28. Regarding the adverse effect of the electric field on the performance of the columns, a technical scheme was designed to avoid their hydrogen embrittlement and plastic reduction.