Electrochemical chloride extraction to repair combined carbonated and chloride contaminated reinforced concrete

The increasing international interest in contemporary architecture has drawn attention to the numerous listed buildings made of reinforced concrete in Europe, and especially in France. The main source of deterioration of this cultural heritage is the corrosion of rebars through carbonation or chloride contamination, but also often by a combination of both. The present study explored this combined corrosion mechanism in reinforced concretes, and investigated Electrochemical Chloride Extraction (ECE) as a technique to stop or decrease corrosion. The analytical approach was based on physico-chemistry, electrochemical measurements, Raman spectroscopy and SEM examinations. The results evidenced the aggressiveness of the combined carbonation and chloride-induced corrosion, and demonstrated the efficiency of the ECE treatment in terms of chloride extraction and reduction of corrosion rate. It appears that ECE treatment only reduces corrosion activity by increasing pH to a value of 10. Nevertheless, the long term durability of the treatment is questionable as the return to a sound concrete passivity is not obtained. (c) 2019 Elsevier Ltd. All rights reserved.