2022 Fiscal Year Final Research Report

Development of anti-corrosive technology for combined deterioration of RC structure and proposal of its maintenance

Research Project

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Project/Area Number	20H02224
Research Category	Grant-in-Aid for Scientific Research (B)
Allocation Type	Single-year Grants
Section	一般
Review Section	Basic Section 22010:Civil engineering material, execution and construction management-related
Research Institution	Kanazawa Institute of Technology
Principal Investigator	Miyazato Shinichi 金沢工業大学, 工学部, 教授 (60302949)
Co-Investigator(Kenkyū-buntansha)	伊藤始富山県立大学, 工学部, 教授 (10553133) 上原子晶久弘前大学, 理工学研究科, 准教授 (70333713) 斎藤豪新潟大学, 自然科学系, 准教授 (90452010)
Project Period (FY)	2020-04-01 – 2023-03-31
Keywords	鉄筋コンクリート / 複合劣化 / 塩害 / ASR / 凍害 / 腐食速度
Outline of Final Research Achievements	As people get older, they can get sick with multiple symptoms. Concrete structures also suffer from combined deterioration of chloride attack, alkali-silica reaction (ASR), and frost attack after long-term use. Although the relationship between combined deterioration and material permeability or cracking has been evaluated so far, steel corrosion has not been evaluated. Based on the above background, this study clarified the corrosion mechanism of reinforced concrete deteriorated with both chloride attack and ASR, or both chloride attack and frost attack. As a result, it was found that the supply of water affects the corrosion rate of rebar under combined deterioration and it was verified that the imperviousness is an important anti-corrosion. It was also clarified that mixing fly ash (FA) is effective as a preventive maintenance measure.
Free Research Field	鉄筋コンクリート工学
Academic Significance and Societal Importance of the Research Achievements	鉄筋コンクリートの複合劣化は、21世紀になって実現象が顕在化し、世界的にも研究が始まったばかりの新分野である。したがって、塩害とASR、また塩害と凍害の影響を受けた鉄筋コンクリートの腐食速度を明らかにした点は、学術的意義と言える。その中で、水の供給の抑制が、複合劣化の進行を遅延させることを明らかにできた点は、インフラの老朽化が社会問題となっている現代の日本において、有効な対策を講じられる社会的意義である。さらに、FAの混和が複合劣化したコンクリートの鉄筋腐食を遅延させることを明らかにできた点は、老朽化対策と副産物の有効活用を兼ねた、時宜を得た社会的意義である。