Electrochemical chloride extraction: efficiency and side effects with differents mineral admixtures

Author(s): Sara Ramos, Isabel Martínez, Ángel Castillo, Marta Castellote
Paper category: Proceedings
Book title: Proceedings of the International RILEM Conference on Materials, Systems and Structures in Civil Engineering Conference segment on Electrochemistry in Civil Engineering
Editor(s): Lisbeth M. Ottosen
ISBN: 978-2-35158-176-6
e-ISBN: 978-2-35158-177-3
Publisher: RILEM Publications SARL
Publication year: 2016
Pages: 100-109
Total Pages: 10
Language : English

Abstract: Deterioration of concrete structures occurs mainly because of contamination caused by salts or other agents that provoke the penetration of ions, such as Cl- through concrete. In addition, electrochemical chloride extraction (ECE) is used as a technique for mitigating chloride-induced corrosion of the reinforcing bars in concrete structures. However, the mechanisms of ion migration, as well as the passivation process are still not well understood. The main objective of this paper is to evaluate the effectiveness of the Electrochemical Chloride Extraction (ECE) process in mortar specimens with various mineral admixtures, evaluating accumulative charged density, free chloride and total chloride content and electrochemical measurements such as Icorr and Ecorr the in all the specimens. To demonstrate the feasibility of applying this technique on full-sized concrete structures and to identify needed improvements to the technology, this research work was tried on four chloride contaminated mortar typologies with different mineral admixtures such as silica fume, fly ash, and slag. For all specimens, an anode system consisting of felt-sandwiched catalysed titanium mesh kept wet by an electrolyte was used. An electrical charge was applied between the anode and the steel bar for different periods on time depending on the admixture. In the specimens fabricated with CEM I with an 8% of replacement in silica fume or fly ash, and CEM I without any additions, the majority of the chloride ions were removed from the concrete at the depth of the steel bars and the re-passivation of the steel was detected by non-destructive electrochemical techniques while the treatment was still connected. For the case of CEM III (with high amount of slag), even after the treatment was applied and the test time was much longer than in the other specimens, free and total chloride content was higher than the allowed in the standards.

Online publication : 2016
Publication type : full_text
Public price (Euros) : 0.00