Investigation on polarization resistance in macro-cell corrosion and protection effect of nitrite ion

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K04555
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22010:Civil engineering material, execution and construction management-related
• Research Institution: Kyushu Institute of Technology
• Principal Investigator: HIBINO MAKOTO 九州工業大学, 大学院工学研究院, 准教授 (90313569)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: マクロセル腐食 / ターフェル勾配 / カソード律速

Outline of Final Research Achievements

The objective of this study is to make corrosion mechanism of steel in concrete clear. In past cases macro-cell corrosion was studied over one-piece steel rod embedded in concrete, so anode and cathode reaction couldn't be investigated separately. In contrast, the author has proposed new experimental method to investigate anode and cathode reaction individually by connecting two concrete blocks which chemical property were deferent. As a result, the reaction rate of anode and cathode could be controlled intentionally, then Tafel slope in macro-cell corrosion could be evaluated. In general concentration of oxygen in concrete is very small, therefore the macro-cell reaction is limited in cathode-control. However, the author has built the activation technique for cathode reaction to reproduce macro-cell corrosion in anode-control. Herewith the reaction rate of anode would be investigated in further detail.

Free Research Field

建設材料学

Academic Significance and Societal Importance of the Research Achievements

本研究の代表的な成果は，鉄筋のマクロセル腐食におけるアノード反応とカソード反応を独立して制御可能としたところである．これによりコンクリート中の鋼材に生じるアノード反応とカソード反応のメカニズムをより詳細に検討できることになった．特に本研究では，カソード反応を活性化する手法を見出し，アノード律速となるマクロセル腐食を再現することに成功している．これにより今まで困難であったアノード反応の分析が可能となった．以上の成果により鉄筋コンクリート構造物の塩害劣化に関する実験方法を多様化することができ，新たな防食工法の開発を支援することができると考えられる．