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Title |
EIS monitoring on corroded reinforcing steel in cement mortar after calcium electro-deposition treatment
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Authors |
김제경(Je-Kyoung Kim) ; 기성훈(Seong-Hoon Kee) ; 이정재(Jurng-Jae Yee) |
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DOI |
https://doi.org/10.11112/jksmi.2019.23.7.1 |
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Keywords |
부식; 교류 임피던스; 침지-건조 반복과정; 시멘트 모르타르; 전착 corrosion; ac impedance; wet-dry cyclic process; cement mortar |
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Abstract |
The primary purposes of this study are to understand a fundamental effects of electro-deposition on reinforcing steel in saturated Ca(OH)2 electrolyte, and evaluate the corrosion rates of rebars under cyclic 3wt.%NaCl immersion and dry corrosion environment. The three cement mortar specimens with cover thickness 5, 10 and 30mm, were prepared in the experiment. To monitor the corrosion rates of rebars in mortar, the three cement mortar specimens were exposed to 110 wet-drying cycles(8-hour-immersion in 3wt.%NaCl and 16-hour-drying in a room temperature) in the laboratory. During the wet-dry cycles, the polarization resistance, Rp, and solution resistance, Rs, were continuously measured. The instantaneous corrosion rates of rebars on the effect of electro-depositing with sat. Ca(OH)2 electrolyte were estimated from obtained R-1p and degrees of wetness were estimated from Rs values. From the experimental results, the corrosion rates of rebars were greatly accelerated by wet/dry cycles. During the mortars exposed to drying condition, the large increases in the corrosion rates were showed at all rebar surfaces in three mortar specimen, attributed from the accelerated reduction rates of dissolved oxygen in drying process. However, the corrosion rates on rebar surface electrochemically deposited with sat. Ca(OH)2 electrolyte showed the clear decreases, caused by calcium deposits in the porous rust layer.
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