Evaluation on Durability of Hot-dip Galvanized Steel Reinforcement in Concrete based on Service Life of Zinc Film

2022 Fiscal Year Final Research Report

• Project/Area Number: 20K22447
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0304:Architecture, building engineering, and related fields
• Research Institution: Tokyo University of Science
• Principal Investigator: CHOE HONGBOK 東京理科大学, 理工学部建築学科, 助教 (60876077)
• Project Period (FY): 2020-09-11 – 2023-03-31
• Keywords: 溶融亜鉛めっき鉄筋 / 防食効果 / 許容腐食量 / 異種間腐食 / マクロセル電流 / 付着強度 / コンクリート品質 / 異形鉄筋の節形状

Outline of Final Research Achievements

In this study, the bond performance and corrosion resistance of hot-dip galvanized steel reinforcement were evaluated for the durability assessment. Concrete mixture and corrosion conditions of steel reinforcement were set as experimental levels. As a result, it was confirmed that bond performance is influenced by the quality of concrete, and it exhibited a behavior where the bond strength increases as the water-cement ratio and unit water content decrease. The corrosion resistance showed a behavior where, under a condition of improved concrete quality by reducing the water-cement ratio, the protective period for the substrate by zinc coating corrosion is prolonged, and local corrosion does not occur until the zinc corrosion reaches 50% of its mass loss. Moreover, it was confirmed that under conditions where galvanic corrosion is a concern due to contact with ordinary steel reinforcement, if there are no concrete cracks, the corrosion behavior is similar to that of general corrosion.

Free Research Field

鉄筋コンクリートの防食性能、付着性能、構造性能評価

Academic Significance and Societal Importance of the Research Achievements

本研究で実施した溶融亜鉛めっき鉄筋の耐久性に関する実験的評価は、亜鉛皮膜における付着性能や防食性能がコンクリートの影響を受けていることを明確に確認できたと考えられる。また、コンクリート条件における亜鉛皮膜の耐久性能を明確に把握することは、鉄筋コンクリート造建築物の耐用年数算定において重要である。このため、本研究の成果はこの点に関する技術的資料を提供しており、本研究によって溶融亜鉛めっき鉄筋の有効活用に際して必要な実質的知見を得られたと考えられる。