| Project/Area Number |
17K06641
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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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| Research Field |
Building structures/Materials
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| Research Institution | Kyoto University |
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Principal Investigator |
Iba Chiemi 京都大学, 工学研究科, 准教授 (10462342)
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| Co-Investigator(Kenkyū-buntansha) |
谷口 円 地方独立行政法人北海道立総合研究機構, 建築研究本部北方 建築総合研究所, 研究主幹 (20462351)
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2019: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2018: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2017: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
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| Keywords | 凍害 / 熱力学 / 過冷却 / DSC / TMA / 多孔質材料 / 熱水分同時移動解析 / 破壊エネルギー / 熱分析 / 示差走査熱量計 / 熱機械分析 / 凍害機構 |
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| Outline of Final Research Achievements |
In this study, we focused on frost damage of porous building materials and tried to quantify the fracture energy of the materials by a thermodynamic approach using a thermal analysis apparatus. The amount of heat dissipation/absorption associated with freezing/thawing of minute specimen was measured using a DSC. Detecting the fracture energy was found difficult due to the precision of the apparatus. In TMA, the relation between the maximum and residual strains and the degree of saturation was investigated using specimens with different water contents.
A freeze-thaw experiment was conducted using a real-size sample to obtain the data of temperature change of the sample. The rapid temperature increase due to elimination of supercooling observed in the experiment was reasonably reproduced by the numerical analysis corresponding to the experiment, in which the ice formation rate obtained by DSC was applied to the existing three-phase heat and moisture simultaneous transfer theory.
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| Academic Significance and Societal Importance of the Research Achievements |
建築材料の分野ではこれまで、凍害の根本的な原因である水の相変化と、材料力学的な局所破壊を共通の物差しとなるエネルギーで論じることはなされておらず、その点を結び付けようとした試みは学術的に意義があると考える。破壊エネルギーを検出するには至らなかったが、今後より精度の高い機器を用いて測定するための基礎情報が得らえた。
また、実験により急激な過冷却解消という現象が凍結による材料損傷の主原因ではないかと推察し、過冷却解消過程の温度変化を数値解析により再現できたことは、今後の過冷却解消時の変形および材料損傷を予測する手法の構築につながる。
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