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2021 年度 実施状況報告書

Modeling and re-corrosion evaluation of patch repaired concrete subjecting to chloride attack

研究課題

研究課題/領域番号 19K04547
研究機関埼玉大学

研究代表者

欒 堯  埼玉大学, 理工学研究科, 助教 (20725288)

研究期間 (年度) 2019-04-01 – 2023-03-31
キーワードchloride migration / patch repaired concrete / blast furnace slag / water repellent agent / water penetration / silica fume
研究実績の概要

In FY2021, the study on the influence of cracks on chloride penetration of patch repaired concrete was continued experimentally. In addition to the specimens made from repair mortar that were studied last fiscal year, the specimens made from ordinary concrete and those blended with supplementary cementitious materials were studied using electrophoresis test for chloride migration. Three types of concrete specimens with ordinary Portland cement (OPC), slag blended cement (BFS), and silica-fume (SF) blended cement were induced with crack width in the range of 0 to 0.6 mm and tested for the effective diffusion coefficient. It was confirmed that the effective diffusion coefficient without crack followed the order of OPC > BFS > SF, while the influence of crack significantly increased with the increasing crack width, playing a dominant role at big crack widths. In addition, chloride binding capacity was studied for repair mortar made from slag blended cement with the replacement ratio of 0 to 70%, showing that the chloride binding capacity strongly depended on slag blending ratio, which may influence the chloride penetration under real conditions.

In addition, the multi-scale approach for capillary absorption of cracked cementitious materials, which were developed in the last fiscal year, was enhanced for the application of water repellent agent to cracked concrete. The analysis indicated that water penetration through cracks was greatly retarded when water repellent agent was added in the mixtures, leading to highly increased water resistance for the repaired structures.

現在までの達成度 (区分)
現在までの達成度 (区分)

4: 遅れている

理由

The progress of experimental and analytical studies on water and chloride penetration of patch repaired concrete generally followed the research plan. On the other hand, regarding the study on the corrosion of steel bars in patch repaired concrete, which was included in the original plan, it was difficult to start experimental study because of the Covid-19. Some necessary apparatuses were delayed being delivered, while the international students who was planned to perform the study couldn’t come to Japan by April, 2022, because of entry closing. Therefore, this study will be focused on FY2022.

今後の研究の推進方策

In the FY2022, immersion test of patch repaired concrete for steel bar corrosion will be conducted to study the influence of cracks on corrosion. Measurement of weight loss and natural potentials for steel bars will be carried out, while chloride profiles will also be measured. The numerical models will also be extended to steel corrosion.

次年度使用額が生じた理由

Some part of the remained amount will be spent on purchasing experiment materials, such as cement, steel bars, chemicals, and so on. The other part will be spent for travel and registration fees for academic conferences.

  • 研究成果

    (3件)

すべて 2022 2021

すべて 学会発表 (3件) (うち国際学会 1件)

  • [学会発表] ひび割れを有するコンクリートの塩化物イオン実効拡散係数に関する実験的研究2022

    • 著者名/発表者名
      周シン,欒堯,王眺,Satya Medepalli,鄭宇倩
    • 学会等名
      土木学会第77回年次学術講演会
  • [学会発表] Study on chemical and physical chloride binding of slag blended cement with different replacement ratios2022

    • 著者名/発表者名
      Yao Luan, Fahmida Parvin
    • 学会等名
      土木学会第77回年次学術講演会
  • [学会発表] Study of hydration and chloride binding properties of slag blended cement2021

    • 著者名/発表者名
      Fahmida Parvin, Yao Luan
    • 学会等名
      8th international symposium on Advances in Civil and Environmental Engineering Practices for Sustainable Development (ACEPS 2021)
    • 国際学会

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公開日: 2022-12-28  

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