The efficiency of chloride extraction using un-galvanized steel anode

Electro-chemical Chloride Extraction (ECE) is considered one of the most effective techniques used to extract chloride ions from reinforced concrete structures. The effectiveness of using ECE depends on some important factors such as anode type, current intensity, extraction duration, type of rebar, and chemical properties of concrete. On the other hand, ECE may cause some detrimental effects on some mechanical properties of concrete and steel such as a reduction in bond and compressive strengths of concrete, and embrittlement (i.e. reduction in ductility) ductility of reinforcing steel. The major aim of this research work was to investigate the effectiveness of ECE using locally available un-galvanized steel mesh with conductive cement paste anode as a new type of anode on a reinforced concrete slab as a structural element. The slab behavior before and after ECE was studied by determining compressive strength, water absorption rate, concrete chloride content, and steel corrosion potential. The slab behavior was studied taking into consideration the established steel arrangement with spacing 20 cm between re-bars. The effect of initial chloride content on chloride extraction efficiency was investigated. Effectiveness of ECE with small initial chloride content 0.4% and 0.8% was compared with that of high initial chloride content 2.5% to know whether the initial chloride content is an important factor in ECE effectiveness or not. (C) 2020 The Authors. Published by Elsevier B.V. on behalf of Faculty of Engineering, Ain Shams University.

Automated summary

Electro-chemical Chloride Extraction (ECE) is an effective technique for extracting chloride ions from reinforced concrete structures, but it may also have detrimental effects on mechanical properties. This study investigated the effectiveness of ECE using a new type of anode, and examined the behavior of slabs and the influence of initial chloride content on extraction efficiency.