| Project/Area Number |
19K04547
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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 22010:Civil engineering material, execution and construction management-related
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| Research Institution | Saitama University |
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Principal Investigator |
Luan Yao 埼玉大学, 理工学研究科, 助教 (20725288)
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| Project Period (FY) |
2019-04-01 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000)
Fiscal Year 2021: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2020: ¥1,820,000 (Direct Cost: ¥1,400,000、Indirect Cost: ¥420,000)
Fiscal Year 2019: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
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| Keywords | patch repaired concrete / repair materials / chloride migration / crack / multi-scale model / water repellency / corrosion / fiber reinforced mortar / chloride penetration / hydrophobic treatment / reinforcement corrosion / chloride / blast furnace slag / water repellent agent / water penetration / silica fume / repair mortar / electrophoresis / capillary absorption / SHCC / simulation / polymer cement / chloride attack / multi-scale modeling |
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| Outline of Research at the Start |
Patch repair is the mostly used method for repairing concrete subject to chloride attack. However, re-corrosion of the repaired concrete in short time is often reported because of inappropriate treatment. This study will focus on establishing an approach of modeling and evaluation of patch repaired concrete. Key factors, for example, chloride transport and the natural potential difference between the old concrete and the repaired part, will be studied. Their effects will be integrated into chloride transport and corrosion models for reasonably evaluating the risk of re-corrosion.
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| Outline of Final Research Achievements |
The research focuses on evaluating chloride transport and corrosion in patch repaired concrete subjected to chloride attack. Experimental investigations include studies on chloride migration in cracked repair mortars as well as the influence of incorporating supplementary cementitious materials (SCMs) and hydrophobic agents. These experiments evaluate factors such as crack width, repair material type, and surface treatments, revealing significant increase in chloride diffusion with increasing crack width and mitigation effect with SCMs and hydrophobic treatments. Numerical simulations using multi-scale models further explore water ingress and chloride penetration in cracked repair mortars. The obtained chloride amount in repaired concrete is used for evaluation of steel rebar corrosion initiation. The simulations provide insights into the influence of crack pattern on water absorption and chloride distribution, crucial for understanding long-term durability.
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| Academic Significance and Societal Importance of the Research Achievements |
Chloride penetration of patch repaired concrete is more complicated than normal concrete, because more factors are involved. Those factors were thoroughly studied, offering important insights for practice. In addition, the numerical approach considers those factors from academic viewpoints.
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