| 研究課題/領域番号 |
19K04547
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| 研究機関 | 埼玉大学 |
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研究代表者 |
欒 堯 埼玉大学, 理工学研究科, 助教 (20725288)
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| 研究期間 (年度) |
2019-04-01 – 2022-03-31
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| キーワード | patch repaired concrete / chloride / repair mortar / crack / electrophoresis / capillary absorption / SHCC / multi-scale model |
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| 研究実績の概要 |
In FY2020, the influence of cracks on chloride penetration of patch repaired concrete was investigated experimentally. Three types of repair mortar with different classes of strength (high, medium, and low), which incorporates acrylic polymer or fiber, were used. The specimens consisted of two layers made from ordinary concrete and repair materials with a crack pre-caused in the later ones. Electrophoresis test showed that the effective diffusion coefficient increased with the increasing crack width. In addition, chloride penetration test due to capillary absorption was performed for beam specimens made from a type of fiber reinforced mortar SHCC that is often used in repair. The influence of bending cracks and sustained loads on the chloride penetration was discussed in the test.
In addition, a multi-scale approach for capillary absorption of cracked SHCC was developed by considering the detailed crack patterns such as the width and location of each crack. Analysis for SHCC with non-uniform crack widths and locations exhibit significant water penetration at crack zones, which is consistent of the observation in past experimental studies. This approach enables the estimation of water profile of cracked SHCC, so can be used for further crack-linked process. The simulation of chloride penetration using this approach will be performed in the future study.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
3: やや遅れている
理由
As written in the research plan, the influence of crack on chloride diffusion coefficient of repair mortar should be studied. In the work of FY2020, such studies were carried out, showing the influence of cracks on the effective diffusion coefficient and chloride penetration due to capillary absorption. In addition, the work about numerical model is another part in the research plan, which was also progressed in FY2020 by establishing capillary absorption model of cracked repair materials.
On the other hand, the study on the corrosion of steel bars in patch repaired concrete shall be launched in FY2020 in the plan, but it was difficult to carry out experimental study in the first half year because of the Covid-19 and lockdown of campus. Therefore, the main experimental study could be only carried out in the second half year mainly for chloride penetration, leaving the experimental study on corrosion delayed. This study will be carried out on FY2021.
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| 今後の研究の推進方策 |
In the FY2021, chloride solution immersion test of patch repaired concrete containing steel bars will be conducted to study the influence of cracks and chloride penetration on corrosion. Chloride profiles in the cracked repair layer will be measured. Measurement of weight loss and natural potentials for steel bars will also be carried out. The numerical models, which were developed in FY2019 and FY2020 for water penetration and chloride diffusion, will also be expanded to steel corrosion.
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| 次年度使用額が生じた理由 |
It was planned to purchase a portable steel corrosion meter in FY2020, but the purchase was not conducted because of the delaying of corrosion experiment. Therefore, in FY2021, the corrosion meter will be purchased for measuring the potential change of steel bars. In addition, an environmental chamber controlling humidity and temperature will be purchased for the environment of the corrosion experiment. In addition, some of the amount will be spent on purchasing experiment materials, for example, cement, steel bars, chemicals, and so on. The other part will be spent for registration fees for academic conferences.
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