| Project/Area Number |
18K05889
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 41030:Rural environmental engineering and planning-related
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| Research Institution | Miyagi University |
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Principal Investigator |
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| Project Period (FY) |
2018-04-01 – 2022-03-31
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| Project Status |
Completed (Fiscal Year 2021)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2020: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2018: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
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| Keywords | コンクリート水利施設 / 石灰石骨材 / 溶脱 / すり減り減量 / 現地調査 / 流速 / ｐH / カルシウムイオン / プレキャストコンクリート製品 / 補修工法 / 表面含浸工法 |
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| Outline of Final Research Achievements |
In irrigation facilities in the Tohoku region where concrete made with limestone (hereinafter referred to as LS) coarse aggregate is used, crater-like depressions have formed as a result of selective leaching of the coarse aggregate underwater.
This study sought to clarify the mechanism of this phenomenon through field surveys, aggregate tests, and replication tests of coarse aggregate leaching using concrete specimen under various flow velocity conditions. In field surveys, leaching was confirmed in a concrete water channel made with coarse LS aggregate. Abrasion test showed that coarse LS aggregate is inferior to andesite coarse aggregate. Leaching replication test using coarse LS aggregate showed that the leaching depth of coarse aggregate is directly proportional to the number of days elapsed and more evident in areas with greater flow velocity; in addition, leaching depth of LS coarse aggregate was predicted as 0.5 mm/year at a flow velocity of 0.5 m/s.
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| Academic Significance and Societal Importance of the Research Achievements |
石灰石を用いたコンクリート構造物は，乾燥収縮が小さく，ひび割れの発生率が少ないことから，優良な材料として評価されてきた。しかし，本研究により石灰石を用いたコンクリート水路において粗骨材が先行して溶脱する変状を初めて明らかにした。すなわち，この劣化現象は，「農業水利施設の機能保全の手引き」にも記載されていない極めて特異で，重度の劣化である。このことは，農業用水利施設のストックマネージメントの観点から極めて重要である。今後、石灰石骨材の利用方法や，劣化対策，補修工法へと研究は展開されると考えられることから，社会的意義は大きい。
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