| 研究課題/領域番号 |
22K04257
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| 研究種目 |
基盤研究(C)
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| 配分区分 | 基金 |
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| 応募区分 | 一般 |
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| 審査区分 |
小区分22010:土木材料、施工および建設マネジメント関連
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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) |
2022-04-01 – 2025-03-31
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| 研究課題ステータス |
交付 (2023年度)
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| 配分額 *注記 |
4,160千円 (直接経費: 3,200千円、間接経費: 960千円)
2024年度: 910千円 (直接経費: 700千円、間接経費: 210千円)
2023年度: 1,170千円 (直接経費: 900千円、間接経費: 270千円)
2022年度: 2,080千円 (直接経費: 1,600千円、間接経費: 480千円)
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| キーワード | self-healing / crack / water penetration / fiber / superabsorbent polymer / X-ray CT / multi-scale model / bacteria / polyvinyl alcohol fiber / water ingress / multi-scale modeling |
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| 研究開始時の研究の概要 |
This study focuses on an approach of modeling the behavior of self-healing concrete under arbitrary wetting/drying environment. Experiment on crack healing and water ingress of the concrete will be performed to obtain the relationship of crack healing rate with water status in cracks. Then, an analytical model coupling water ingress and crack healing will be developed, incorporating the time-dependent change of crack width and other parameters. It is expected that water spatial distribution in concrete and crack healing process with time under arbitrary environment can be simulated reasonably.
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| 研究実績の概要 |
In FY2023, experimental study was performed on the performance of strain-hardening cementitious composites (SHCC) with the addition of superabsorbent polymers (SAPs), which were expected to accelerate self-healing of SHCCs. Uniaxial tensile test was performed to induce multiple fine cracks, subsequently immersing the specimens in water for self-healing. Three types of SAPs were used, respectively, with experiment showing difference in self-healing rate depending on water absorption property of SAP. In addition to microscopic observation on crack healing at surface, X-ray computed tomography (CT) was applied to study the internal healing inside specimens. Based on the information of initial cracks and crack healing rate from the experiment, simulation based on multi-scale models coupling crack healing and water ingress were carried out for the SHCCs with SAPs, reasonably representing self-healing process and the consequent water ingress reduction. Furthermore, the multi-scale model was enhanced to consider the incorporation of integral silane treatment on water repellency of cracked SHCCs, which has been shown effective to increase water resistance for durability. Comparison between the performed simulation and test data from past studies showed the validity of the simulation on water absorption behaviors of treated SHCCs.
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| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
Based on the multi-scale model developed in last fiscal year, more complicated conditions that influence water ingress or self-healing were taken into account in the simulation by enhancing the present model from microscale, such as the influence of SAPs and the incorporation of silane treatment. The simulation on those cases were compared with experiment performed in this year or test data from past studies, indicating the reasonability of the simulation result. It can be said that the scope of the model has been extended for more applications.
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| 今後の研究の推進方策 |
In FY2024, self-healing experiment will be performed under outdoor condition for longer time using SHCC specimens with the addition of SAPs, i.e. above half year compared to several weeks of current experiment. It is expected that the self-healing process could be much slower than experiment in laboratory, because of less available water outdoor. Meanwhile, self-healing experiment in laboratory will be continued using SAP-added SHCCs under high relative humidity of atmosphere. It is expected that water release from SAPs at high relative humidity will promote self-healing, even that the rate may be much less than immersion in water. Thermogravimetric analysis (TG) and X-ray computed tomography (CT) will be used to analyze chemical composition of healing product and crack morphology, respectively. Neutron radiography will be used to observe water distribution in cracks. Based on the experiment results, it is planned to enhance the multi-scale model for simulation under outdoor condition as well as the influence of high relative humidity.
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