2021 Fiscal Year Final Research Report
Preventive maintenance management of RC structures based on corrosion onset conditions of steel bars
| Project/Area Number |
19H02218
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 22010:Civil engineering material, execution and construction management-related
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| Research Institution | Tokyo University of Science |
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Principal Investigator |
KATO YOSHITAKA 東京理科大学, 理工学部土木工学科, 教授 (80272516)
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| Co-Investigator(Kenkyū-buntansha) |
伊代田 岳史 芝浦工業大学, 工学部, 教授 (20549349)
加藤 絵万 国立研究開発法人海上・港湾・航空技術研究所, 港湾空港技術研究所, グループ長 (90371765)
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| Project Period (FY) |
2019-04-01 – 2022-03-31
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| Keywords | 鉄筋腐食 / コンクリート / 飽水度 |
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| Outline of Final Research Achievements |
The purpose of this study was to organize the conditions for corrosion of steel bars embedded in concrete and to develop a method for estimating the corrosion onset time of steel bars. As research results, the relationship between the chloride ion concentration and oxygen concentration on the corrosion condition was experimentally obtained. It was also found that the corrosion rate of steel reached a maximum when the water saturation of pore in hardened cement composites at surface of the steel was 60-80%. Furthermore, it was found that the action of external liquid water is indispensable for the corrosion of the steel bars to progress when the hardened cement composites is dry. The study concluded that it is extremely important to understand the drying condition of hardened cement composites, and that it is possible to predict the degree of drying of concrete in actual structures based on meteorological information and concrete properties.
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| Free Research Field |
コンクリート工学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究の学術的な意義は，セメント硬化体中の鉄筋について，発錆条件および腐食速度に与える影響を精密な実験に基づいて定量的に整理したことにある．この結果，腐食リスクのあるRC構造物の維持管理においては，コンクリートの乾燥状態と，液体としての水の作用に着目することが極めて重要であることを明らかにした．また，申請時の計画では想定できなかったために研究期間内では完遂できなかったが，バルク法に着目し，気象情報とコンクリートの特性値から，実構造物のコンクリートの乾燥程度を予測できる可能性を見いだした．今後，この方法を発展させることで，実構造物の維持管理において活用できる技術になりえると考えている．
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