Evaluation of the threshold limit of steel corrosion in concrete structure after desalination based on ion balance and extending the service life

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K15061
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 22010:Civil engineering material, execution and construction management-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Nakayama Kazuhide 東京工業大学, 環境・社会理工学院, 助教 (10835408)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 脱塩工法 / 塩害 / 発錆限界塩化物イオン濃度 / 鉄筋防食効果 / イオン分布

Outline of Final Research Achievements

The threshold limit of steel corrosion in concrete after desalination was evaluated using [Cl-]/[OH-] and various electrochemical corrosion indexes. The results of the experiments using aqueous solutions suggest that the corrosion resistance of the passive film may differ significantly around pH 12.5 for a constant chloride ion concentration. It was also found that the potential of the rebar also greatly affected the corrosion resistance of the passive film. The trends of corrosion behavior in aqueous solution and in mortar were generally the same.
The steel corrosion resistance in concrete after desalination may be improved compared to that in ordinary concrete if the steel potential is the same.

Free Research Field

コンクリート工学

Academic Significance and Societal Importance of the Research Achievements

脱塩後コンクリート中の鉄筋腐食発生限界について，［Cl-］/［OH-］ならびに電気化学的指標を用いて評価，検討した点に学術的意義がある。本研究で得られた結果は，脱塩後コンクリートのみならず高アルカリ環境下にあるコンクリート中の鉄筋の腐食抵抗性について理解を深めることに繋がり，ひいては，塩害環境下にあるコンクリート構造物の長寿命化に資する。