Measurement of limit ion concentration for steel corrosion in existing concrete by modified iron powder dispersion method

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K06523
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Civil engineering materials/Construction/Construction management
• Research Institution: Kisarazu National College of Technology
• Principal Investigator: AOKI Yusuke 木更津工業高等専門学校, 環境都市工学科, 教授 (70360328)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 塩害 / 鉄粉散布法 / 鋼材腐食発生限界塩化物イオン濃度 / 塩化物イオン

Outline of Final Research Achievements

The limit ion concentration for steel corrosion in existing concrete is an important value for determining and predicting salt damage in concrete structures. The principal investigator devised a method called iron powder dispersion method for measuring the limit chloride ion concentration, and further improved the method. The purpose of this study was to demonstrate the practicality of the method.
Some specimens embedding rebar in mortar was prepared , and salt water was continuously infiltrated into the its specimens.The self-potential of rebar was continuously measured to identify the sorrosion initiation time of rebar. Immediately, the specimen was split, and the above method was performed on the split surface. As a result, the ideal experimental result was obtained that the corrosion of rebar initiated when the corrosion range of the iron powder dispased on the split surface reached the surface of the rebar. We will continue to investigate.

Free Research Field

コンクリート工学

Academic Significance and Societal Importance of the Research Achievements

今回の研究では実用性を完全に実証するには至らなかったが，本研究で検討してきた「改良版・鉄粉散布法」の実用性が実証され，任意の既設コンクリート中の鋼材腐食発生限界塩化物イオン濃度を測定できるようになれば，今後のコンクリート構造物の塩害の判定や予測に，大きな進展を生み出せるものと考えている。今後も，研究を継続していきたい。