研究者紹介システム

福井 一真
フクイ カズマ
大学院工学研究科 建築学専攻
助教
土木・建築工学関係
Last Updated :2022/09/16

研究者情報

所属

  • 【主配置】

    大学院工学研究科 建築学専攻
  • 【配置】

    工学部 建築学科

学位

  • 博士(工学), 京都大学
  • 凍結融解作用による建築材料の劣化機構とその抑制方法

授業科目

研究活動

研究キーワード

  • 凍害
  • 湿気
  • 建築環境工学

研究分野

  • 社会基盤(土木・建築・防災) / 建築環境、建築設備

論文

  • Kazuma Fukui, Chiemi Iba, Madoka Taniguchi, Kouichi Takahashi, Daisuke Ogura

    In this study, supercooling effects on the hygrothermal behavior of fired clay materials under various experimental conditions, such as water content, cooling rates, and size of specimens were investigated using experimental methods and hygrothermal simulations. We report results of the differential scanning calorimetry (DSC) and temperature distribution changes during a freeze-thaw (FT) experiment using unsaturated specimens. Also, we developed a numerical model of the freezing and thawing processes including the supercooling processes. The DSC results show the freezing of the supercooled water in a fired clay material is considerably faster than that in cement-based materials. It was also found that the dependency of the supercooling effects on the cooling rates seemed to be small. When the water saturation of a material decreases, the rate of the ice saturation increase during the freezing of the supercooled water is decreased while the freezing points of the supercooled water was not changed considerably. The comparison of the results of the FT experiment and hygrothermal simulations show that the combination of the existed hygrothermal model and a modified kinetic equation can reproduce the rapid temperature rise during the freezing of the supercooling water in the FT experiment. Finally, the size effects of specimens on the supercooling phenomenon was discussed based on the experimental and calculation results. The freezing points got higher when a specimen was larger. Due to differences in the ratio of the surface area to the volume, hygrothermal behavior in small specimens and relatively large specimens like that of the DSC and the FT experiment, respectively were markedly different. Water in a relatively large specimen with a small ratio of surface area to volume can achieve the thermodynamic equilibrium in a short period after the freezing starts.

    SAGE PUBLICATIONS LTD, 2021年10月05日, JOURNAL OF BUILDING PHYSICS, 英語

    研究論文(学術雑誌)

  • Kazuma Fukui, Chiemi Iba, Shuichi Hokoi, Daisuke Ogura

    The effect of air pressure on moisture transfer inside porous building materials cannot be omitted in cases where air cannot escape through the surface of the materials; in such cases, air is compressed by the movement of moisture. In this study, we conducted water-absorption tests on a brick specimen. By comparing the result of the experiment on a specimen whose side surfaces were sealed with that of a specimen whose bottom surface was additionally sealed, it was demonstrated that the water-absorption was evidently delayed in the latter case, wherein air could not escape from the specimen except for the top surface, through which water was absorbed. We also developed a numerical model based on the equations for simultaneous air and moisture transfer. The calculated result is reasonably consistent with the experimental result, which supports the validity of the model that includes the change in air pressure in the material and air loss through the top surface as air bubbles. By using this model, the behavior of the air and water inside the specimen was investigated in detail.

    WILEY, 2018年10月, JAPAN ARCHITECTURAL REVIEW, 1 (4), 538 - 547, 英語

    研究論文(学術雑誌)

  • 福井 一真, 伊庭 千恵美, 鉾井 修一, 小椋 大輔

     The effect of air pressure on moisture transfer inside porous building materials cannot be ignored in cases where air cannot escape through the surfaces of the materials; in such cases, air is compressed by the movement of the moisture. Such a situation can be brought about by the sealing or surface-protecting materials that prevent water from penetrating into a surface, which is often seen in a typical water absorption test. However, in the field of architectural engineering, the effect of air pressure under wetting processes has not been sufficiently examined, and the validity of calculation models for the transfer of both air and moisture inside materials has not yet been verified. Therefore, this study investigates the behavior of water under the influence of air-pressure changes and develops a proper calculation model for it.
     First, we conducted two types of water absorption tests on bricks. In both of the tests, water infiltrated the specimens through their top surfaces, and the time profiles of the water content were measured using a gamma-ray attenuation method. While only the side surfaces of the specimen were impermeable to moisture and air in Case 1, the side and bottom surfaces were impermeable in Case 2. In Case 2, we expected the air pressure inside the specimen to increase, as the air inside it would not be able to escape through the bottom; this would result in the infiltration of the water being prevented. The results for Case 2 show that the moisture resistance of the specimen was seemingly greater than those obtained in Case 1. We also discovered that the amount of water that was absorbed during Case 2 was not significantly different from the amount absorbed during Case 1. Because air bubbles were observed to have escaped through the water on the top surface in Case 2, we determined that the air pressure inside the specimen returned to atmospheric pressure over time. Therefore, we expected the steady states of Cases 1 and 2 to be similar. It should be noted that the measured water content in Case 2 varied depending on the horizontal position of the measurements.
     Second, we developed a calculation model corresponding to the experiment that was based on the equation for the transfer of both air and liquid water. The calculation results show that the increase in the water content slowed significantly when the changes in the air pressure inside a material were considered. In addition, the calculated and measured water contents agreed well with one another and allowed us to verify the validity of our model. The analysis also showed that when air escapes from the material, the amount that escapes should be adequately considered by the calculation model. According to the results of both the experiments and the simulation, the infiltration process under the influence of the air pressure was as follows: At an early stage in the infiltration process, because the air pressure inside the material was not much higher than atmospheric pressure, water infiltration was not prevented significantly. However, this caused a rapid compression of the air inside the specimen, which resulted in high air pressure within it. This trend reduced the rate of the increase of the air pressure because further water infiltration was reduced by the high pressure. During the final stage of the infiltration, the air pressure began to decrease to atmospheric pressure and water content reached almost the same values as those in Case 1.

    日本建築学会, 2018年01月, 日本建築学会環境系論文集, (743), 39 - 47, 日本語

MISC

  • Kazuma Fukui, Chiemi Iba, Madoka Taniguchi, Kouichi Takahashi, Daisuke Ogura

    To investigate the supercooling phenomenon in fired clay materials, low-temperature differential scanning calorimetry (DSC) and a one-dimensional freeze-thaw (FT) experiment were performed on saturated specimens. The rate of increase in ice saturation during freezing was calculated from the DSC result. Rapid ice growth over a relatively narrow temperature range (within about 0.2 K) was observed at a cooling rate of 0.25 K/min In the FT experiment, the temperature distribution of a specimen was measured with inserted thermocouples. According to the results of the FT experiment, a rapid temperature increase was observed at sub-zero temperatures accompanied by freezing of the supercooled water. When the supercooled water began to freeze, the released latent heat was found to strongly prevent the specimen temperature from dropping even during the cooling period. Finally, a hygrothermal model of freezing and thawing including a non-equilibrium supercooling process was developed. The freezing rate of the supercooled water was modelled based on the DSC result. The validity of the model was verified by comparing the results of the FT experiment and calculations. The model was found to be able to replicate the rapid temperature rise during the cooling period of the FT experiment.

    E D P SCIENCES, 2020年, 12TH NORDIC SYMPOSIUM ON BUILDING PHYSICS (NSB 2020), 172, 英語

  • Koki Yamada, Chiemi Iba, Tomoko Uno, Kazuma Fukui, Daisuke Ogura

    The former Koshien Hotel is an historic Japanese architectural structure, where two different tuffs called Nikkaseki and Tatsuyamaishi were used to build the exterior. Despite its cultural significance, the building's exterior is deteriorating in many ways, with water permeation being the main factor. In this study, the hygrothermal properties of both Nikkaseki and Tatsuyamaishi were measured in order to examine the correlation between deterioration mechanisms and the tuff characteristics in detail. The basic physical properties, pore size distribution, vapor permeability, hydraulic conductivity, and sorption isotherm were measured. The results of a comparison of two tuffs led us to hypothesize that the main reason behind Nikkaseki's deterioration is expansive freezing, while that of Tatsuyamaishi is caused by repeating dehydration or dry-wet cycles.

    E D P SCIENCES, 2020年, 12TH NORDIC SYMPOSIUM ON BUILDING PHYSICS (NSB 2020), 172, 英語

  • 凍結融解による材料変形と温度条件および含水率の関係の検討 熱力学的アプローチによる多孔質材料の凍害機構の検討 その3

    伊庭千恵美, 福井一真, 谷口円, 高橋光一, 小椋大輔

    2020年, 日本建築学会大会学術講演梗概集・建築デザイン発表梗概集(CD-ROM), 2020

  • 凝灰岩の熱伝導率と平衡含水率の測定 旧甲子園ホテルの外装材保存に関する研究 その3

    山田皓貴, 伊庭千恵美, 宇野朋子, 福井一真, 小椋大輔

    2020年, 日本建築学会大会学術講演梗概集・建築デザイン発表梗概集(CD-ROM), 2020

  • 水で飽和した焼成材料内の過冷却を考慮した熱水分同時移動モデル

    福井一真, 伊庭千恵美, 谷口円, 高橋光一, 小椋大輔

    2020年, 日本建築学会大会学術講演梗概集・建築デザイン発表梗概集(CD-ROM), 2020

  • 甲子園会館に用いられる凝灰岩外装材の保存に関する研究-現地環境条件調査と物性値測定による劣化メカニズムの検討-

    山田皓貴, 伊庭千恵美, 宇野朋子, 福井一真, 小椋大輔

    2020年, 日本文化財科学会大会研究発表要旨集, 37th

  • 41011 4種類の材料の凍結融解過程のエネルギー変化と変形挙動 熱力学的アプローチによる多孔質材料の凍害機構の検討 その2

    伊庭 千恵美, 福井 一真, 谷口 円, 高橋 光一, 小椋 大輔

    日本建築学会, 2019年07月20日, 環境工学II, (2019), 21 - 22, 日本語

  • 41033 外装材に使用される凝灰岩の熱水分物性値 旧甲子園ホテルの外装材保存に関する研究 その2

    山田 皓貴, 伊庭 千恵美, 宇野 朋子, 福井 一真, 小椋 大輔

    日本建築学会, 2019年07月20日, 環境工学II, (2019), 65 - 66, 日本語

  • Kazuma Fukui, Chiemi Iba, Madoka Taniguchi, Kouichi Takahashi, Daisuke Ogura

    Frost action is one of the main causes for deterioration of porous building materials under defined hygrothermal conditions. For an accurate assessment of the frost damage risk under various environmental conditions, thermal, moisture, and mechanical properties should be considered; the hygrothermal properties affect the distribution of temperature and amount of frozen water in the material, whereas the mechanical properties are necessary to predict deformation and damage. Moreover, the dependency of these properties on the moisture content should be understood. Therefore, in this study, thermal, moisture, and mechanical properties of wet and dry fired clay materials were measured. The fired clay materials were sintered at two different temperatures, 1000 degrees C and 1100 degrees C (samples T10 and T11, respectively) for comparison. The measured thermal and mechanical properties are considerably different in the wet state compared to the dry state. Freeze-thaw tests were conducted to investigate the relation between the material properties and the frost resistance under a simple experimental condition. As expected, based on the pore structure and obtained mechanical properties, T10 exhibited lower frost resistance than T11 in the freeze-thaw test. Finally, frost damage risk was assessed under various environmental conditions based on the obtained hygrothermal and mechanical properties.

    E D P SCIENCES, 2019年, 4TH CENTRAL EUROPEAN SYMPOSIUM ON BUILDING PHYSICS (CESBP 2019), 282, 英語

  • 41060 多孔質建築材料内の空気圧が水分移動に与える影響の検討 ピンホールの形状と吸水速度の関係

    福井 一真, 伊庭 千恵美, 鉾井 修一, 小椋 大輔

    日本建築学会, 2018年07月20日, 環境工学II, (2018), 119 - 120, 日本語

  • 41063 熱力学的アプローチによる多孔質材料の凍害機構の検討 その1 試料の特性とDSC測定条件の検討

    伊庭 千恵美, 福井 一真, 谷口 円

    日本建築学会, 2018年07月20日, 環境工学II, (2018), 125 - 126, 日本語

  • 多孔質建築材料内の空気圧が水分移動に与える影響の検討 ピンホールを設けた試験体の吸水実験と空気・水分同時移動解析

    福井 一真, 伊庭 千恵美, 鉾井 修一, 小椋 大輔

    日本建築学会, 2018年06月23日, 日本建築学会近畿支部研究報告集. 環境系, (58), 141 - 144, 日本語

  • 41073 表面含浸材が多孔質建築材料内の空気圧および水分移動に与える影響の検討 空気圧を考慮した水分移動の解析

    福井 一真, 伊庭 千恵美, 鉾井 修一, 小椋 大輔

    日本建築学会, 2017年07月20日, 環境工学II, (2017), 175 - 176, 日本語

  • 表面含浸材が多孔質建築材料内の空気圧および水分移動に与える影響の検討

    福井 一真, 伊庭 千恵美, 鉾井 修一, 小椋 大輔

    日本建築学会, 2017年06月24日, 日本建築学会近畿支部研究報告集. 環境系, (57), 17 - 20, 日本語

  • Kazuma Fukui, Chiemi Iba, Shuichi Hokoi

    The application of penetrating water repellent sometimes accelerates degradation of building materials, especially when there are water sources inside such as ground water. A series of experiments using the gamma-ray attenuation method and numerical analysis corresponding to the experiments were performed to reveal the moisture behavior in building materials treated with silane water repellent and to develop a proper numerical model for the repellent layer. The experimental and calculation results show a large difference in water content between the repellent layer and the substrate, which may cause the abovementioned problems. (c) 2017 The Authors. Published by Elsevier Ltd.

    ELSEVIER SCIENCE BV, 2017年, 11TH NORDIC SYMPOSIUM ON BUILDING PHYSICS (NSB2017), 132, 735 - 740, 英語

  • 防水・撥水剤が建築材料内の水分移動・蓄積に与える影響(その1) 浸透系撥水剤の液相水分伝導率

    福井 一真, 伊庭 千恵美, 吉岡 瑞穂, 鉾井 修一

    日本建築学会, 2016年08月24日, 環境工学II, (2016), 503 - 504, 日本語

  • 防水・撥水剤が建築材料内の水分移動・蓄積に与える影響 (その1)-浸透系撥水剤の液相水分伝導率-

    福井 一真, 伊庭 千恵美, 吉岡 瑞穂, 鉾井 修一

    日本建築学会, 2016年06月25日, 日本建築学会近畿支部研究報告集. 環境系, (56), 165 - 168, 日本語

  • Chiemi Iba, Kazuma Fukui, Shuichi Hokoi

    Water-repellent agents are considered an effective measure of preventing moisture damage in building materials. However, data on the moisture transfer characteristics of repellent materials are insufficient. This study focused on the transfer of liquid water in a porous building material and quantitatively evaluated the applicability of a water-repellent consolidant as a protection agent via water infiltration experiments and numerical analysis. The experimental results could be reproduced by treating the water-repellent consolidant as having two layers with different water conductivities.

    AMER INST PHYSICS, 2016年, THERMOPHYSICS 2016: 21ST INTERNATIONAL MEETING, 1752, 英語

  • 屋外文化財への適用を目的とした撥水剤処理された建築材料の曝露試験

    福井一真, 伊庭千恵美, 吉岡瑞穂, 鉾井修一

    2016年, 日本文化財科学会大会研究発表要旨集, 33rd

  • 凍結融解過程の焼成材料の変形の異方性 熱水分・力学連成解析における物性値の異方性の考慮

    福井一真, 伊庭千恵美, 小椋大輔

    2021年, 日本建築学会大会学術講演梗概集・建築デザイン発表梗概集(CD-ROM), 2021

  • 旧甲子園ホテルの外装材保存に関する研究 その4 凝灰岩の液相水分伝導率の同定

    倉橋哲, 伊庭千恵美, 山田皓貴, 宇野朋子, 福井一真, 小椋大輔

    2021年, 日本建築学会大会学術講演梗概集・建築デザイン発表梗概集(CD-ROM), 2021

  • 旧甲子園ホテルの外装材保存に関する研究 その5 凝灰岩内部の熱水分移動の検討

    山田皓貴, 伊庭千恵美, 宇野朋子, 福井一真, 倉橋哲, 小椋大輔

    2021年, 日本建築学会大会学術講演梗概集・建築デザイン発表梗概集(CD-ROM), 2021

講演・口頭発表等

  • Investigation on the Deterioration Mechanism of Tuff Stones Used for the Exteriors at the Former Koshien Hotel

    Koki Yamada, Chiemi Iba, Tomoko Uno, Kazuma Fukui, Daisuke Ogura

    12TH NORDIC SYMPOSIUM ON BUILDING PHYSICS (NSB 2020), 2020年, 英語, E D P SCIENCES, The former Koshien Hotel is an historic Japanese architectural structure, where two different tuffs called Nikkaseki and Tatsuyamaishi were used to build the exterior. Despite its cultural significance, the building's exterior is deteriorating in many ways, with water permeation being the main factor. In this study, the hygrothermal properties of both Nikkaseki and Tatsuyamaishi were measured in order to examine the correlation between deterioration mechanisms and the tuff characteristics in detail. The basic physical properties, pore size distribution, vapor permeability, hydraulic conductivity, and sorption isotherm were measured. The results of a comparison of two tuffs led us to hypothesize that the main reason behind Nikkaseki's deterioration is expansive freezing, while that of Tatsuyamaishi is caused by repeating dehydration or dry-wet cycles.

  • Experimental investigation and hygrothermal modelling of freeze-thaw process of saturated fired clay materials including supercooling phenomenon

    Kazuma Fukui, Chiemi Iba, Madoka Taniguchi, Kouichi Takahashi, Daisuke Ogura

    12TH NORDIC SYMPOSIUM ON BUILDING PHYSICS (NSB 2020), 2020年, 英語, E D P SCIENCES, To investigate the supercooling phenomenon in fired clay materials, low-temperature differential scanning calorimetry (DSC) and a one-dimensional freeze-thaw (FT) experiment were performed on saturated specimens. The rate of increase in ice saturation during freezing was calculated from the DSC result. Rapid ice growth over a relatively narrow temperature range (within about 0.2 K) was observed at a cooling rate of 0.25 K/min In the FT experiment, the temperature distribution of a specimen was measured with inserted thermocouples. According to the results of the FT experiment, a rapid temperature increase was observed at sub-zero temperatures accompanied by freezing of the supercooled water. When the supercooled water began to freeze, the released latent heat was found to strongly prevent the specimen temperature from dropping even during the cooling period. Finally, a hygrothermal model of freezing and thawing including a non-equilibrium supercooling process was developed. The freezing rate of the supercooled water was modelled based on the DSC result. The validity of the model was verified by comparing the results of the FT experiment and calculations. The model was found to be able to replicate the rapid temperature rise during the cooling period of the FT experiment.

  • 水で飽和した焼成材料内の過冷却を考慮した熱水分同時移動モデル

    福井一真, 伊庭千恵美, 谷口円, 高橋光一, 小椋大輔

    日本建築学会大会学術講演梗概集・建築デザイン発表梗概集(CD-ROM), 2020年

  • 凝灰岩の熱伝導率と平衡含水率の測定 旧甲子園ホテルの外装材保存に関する研究 その3

    山田皓貴, 伊庭千恵美, 宇野朋子, 福井一真, 小椋大輔

    日本建築学会大会学術講演梗概集・建築デザイン発表梗概集(CD-ROM), 2020年

  • 凍結融解による材料変形と温度条件および含水率の関係の検討 熱力学的アプローチによる多孔質材料の凍害機構の検討 その3

    伊庭千恵美, 福井一真, 谷口円, 高橋光一, 小椋大輔

    日本建築学会大会学術講演梗概集・建築デザイン発表梗概集(CD-ROM), 2020年

  • 41033 外装材に使用される凝灰岩の熱水分物性値 旧甲子園ホテルの外装材保存に関する研究 その2

    山田 皓貴, 伊庭 千恵美, 宇野 朋子, 福井 一真, 小椋 大輔

    環境工学II, 2019年07月20日, 日本語, 日本建築学会

  • 41011 4種類の材料の凍結融解過程のエネルギー変化と変形挙動 熱力学的アプローチによる多孔質材料の凍害機構の検討 その2

    伊庭 千恵美, 福井 一真, 谷口 円, 高橋 光一, 小椋 大輔

    環境工学II, 2019年07月20日, 日本語, 日本建築学会

  • Investigation of thermal, moisture, and mechanical properties of wet and dry fired clay materials to assess frost damage risk

    Kazuma Fukui, Chiemi Iba, Madoka Taniguchi, Kouichi Takahashi, Daisuke Ogura

    4TH CENTRAL EUROPEAN SYMPOSIUM ON BUILDING PHYSICS (CESBP 2019), 2019年, 英語, E D P SCIENCES, Frost action is one of the main causes for deterioration of porous building materials under defined hygrothermal conditions. For an accurate assessment of the frost damage risk under various environmental conditions, thermal, moisture, and mechanical properties should be considered; the hygrothermal properties affect the distribution of temperature and amount of frozen water in the material, whereas the mechanical properties are necessary to predict deformation and damage. Moreover, the dependency of these properties on the moisture content should be understood. Therefore, in this study, thermal, moisture, and mechanical properties of wet and dry fired clay materials were measured. The fired clay materials were sintered at two different temperatures, 1000 degrees C and 1100 degrees C (samples T10 and T11, respectively) for comparison. The measured thermal and mechanical properties are considerably different in the wet state compared to the dry state. Freeze-thaw tests were conducted to investigate the relation between the material properties and the frost resistance under a simple experimental condition. As expected, based on the pore structure and obtained mechanical properties, T10 exhibited lower frost resistance than T11 in the freeze-thaw test. Finally, frost damage risk was assessed under various environmental conditions based on the obtained hygrothermal and mechanical properties.

  • 41063 熱力学的アプローチによる多孔質材料の凍害機構の検討 その1 試料の特性とDSC測定条件の検討

    伊庭 千恵美, 福井 一真, 谷口 円

    環境工学II, 2018年07月20日, 日本語, 日本建築学会

  • 41060 多孔質建築材料内の空気圧が水分移動に与える影響の検討 ピンホールの形状と吸水速度の関係

    福井 一真, 伊庭 千恵美, 鉾井 修一, 小椋 大輔

    環境工学II, 2018年07月20日, 日本語, 日本建築学会

  • 多孔質建築材料内の空気圧が水分移動に与える影響の検討 ピンホールを設けた試験体の吸水実験と空気・水分同時移動解析

    福井 一真, 伊庭 千恵美, 鉾井 修一, 小椋 大輔

    日本建築学会近畿支部研究報告集. 環境系, 2018年06月23日, 日本語, 日本建築学会

  • 41073 表面含浸材が多孔質建築材料内の空気圧および水分移動に与える影響の検討 空気圧を考慮した水分移動の解析

    福井 一真, 伊庭 千恵美, 鉾井 修一, 小椋 大輔

    環境工学II, 2017年07月20日, 日本語, 日本建築学会

  • 表面含浸材が多孔質建築材料内の空気圧および水分移動に与える影響の検討

    福井 一真, 伊庭 千恵美, 鉾井 修一, 小椋 大輔

    日本建築学会近畿支部研究報告集. 環境系, 2017年06月24日, 日本語, 日本建築学会

  • Moisture behavior inside building materials treated with silane water repellent

    Kazuma Fukui, Chiemi Iba, Shuichi Hokoi

    11TH NORDIC SYMPOSIUM ON BUILDING PHYSICS (NSB2017), 2017年, 英語, ELSEVIER SCIENCE BV, The application of penetrating water repellent sometimes accelerates degradation of building materials, especially when there are water sources inside such as ground water. A series of experiments using the gamma-ray attenuation method and numerical analysis corresponding to the experiments were performed to reveal the moisture behavior in building materials treated with silane water repellent and to develop a proper numerical model for the repellent layer. The experimental and calculation results show a large difference in water content between the repellent layer and the substrate, which may cause the abovementioned problems. (c) 2017 The Authors. Published by Elsevier Ltd.

  • 防水・撥水剤が建築材料内の水分移動・蓄積に与える影響(その1) 浸透系撥水剤の液相水分伝導率

    福井 一真, 伊庭 千恵美, 吉岡 瑞穂, 鉾井 修一

    環境工学II, 2016年08月24日, 日本語, 日本建築学会

  • 防水・撥水剤が建築材料内の水分移動・蓄積に与える影響 (その1)-浸透系撥水剤の液相水分伝導率-

    福井 一真, 伊庭 千恵美, 吉岡 瑞穂, 鉾井 修一

    日本建築学会近畿支部研究報告集. 環境系, 2016年06月25日, 日本語, 日本建築学会

  • Moisture Characteristics of Water-repellent Consolidants and their Applicability to Existing Buildings

    Chiemi Iba, Kazuma Fukui, Shuichi Hokoi

    THERMOPHYSICS 2016: 21ST INTERNATIONAL MEETING, 2016年, 英語, AMER INST PHYSICS, Water-repellent agents are considered an effective measure of preventing moisture damage in building materials. However, data on the moisture transfer characteristics of repellent materials are insufficient. This study focused on the transfer of liquid water in a porous building material and quantitatively evaluated the applicability of a water-repellent consolidant as a protection agent via water infiltration experiments and numerical analysis. The experimental results could be reproduced by treating the water-repellent consolidant as having two layers with different water conductivities.

  • Effects of anisotropy of properties of fired clay materials on strain evolution and results of coupled hygrothermal and mechanical simulations during freezing and thawing

    Kazuma Fukui, Chiemi Iba, Daisuke Ogura

    8th International Building Physics Conference, 2021年, 英語

    口頭発表(一般)

所属学協会

  • 日本建築学会

    2016年04月 - 現在

共同研究・競争的資金等の研究課題

  • 熱水分移動と応力・ひずみ変化の連成解析による組積造建築の凍害メカニズムの検討

    福井 一真

    日本学術振興会, 科学研究費助成事業 研究活動スタート支援, 研究活動スタート支援, 神戸大学, 2021年08月30日 - 2023年03月31日

  • 過冷却とエネルギー授受を考慮した建築材料の凍結破壊の動的メカニズムの検討

    伊庭 千恵美, 谷口 円, 高橋 光一

    日本学術振興会, 科学研究費助成事業 基盤研究(C), 基盤研究(C), 京都大学, 2020年04月01日 - 2023年03月31日

  • 建築物の凍結融解による劣化の予測モデルの構築と抑制方法の提案

    福井 一真

    日本学術振興会, 科学研究費助成事業 特別研究員奨励費, 特別研究員奨励費, 京都大学, 2019年04月 - 2021年03月, 研究代表者

    建築材料の凍害は、材料内の水分が凍結と融解を繰り返すことで表面の剥離や亀裂、壁体の剥落などを引き起こす現象である。本研究では、実環境下にある建築部材に適用可能な凍結融解過程の材料の力学挙動の予測モデルを構築することで凍害のリスクを定量化し、その抑制方法を提案することを目的としている。当該年度には、(1)建築材料の凍結による破壊のメカニズムの検討と、(2)過冷却を考慮した建築材料内の熱水分移動の解析モデルの構築を行った。 まず、(1)について、熱分析手法である示差走査熱量測定(DSC)および熱機械分析(TMA)と、凍結融解実験を様々な建築材料を用いて行い、凍結融解過程のエネルギー変化とひずみ変化、凍結融解実験における破壊性状の比較を行った。DSCとTMAでは、すべての材料で内部の水分が過冷却を起こし、凍結時に急激な潜熱の放出と膨張が起こったことから、過冷却水の急速な凍結が材料の損傷に影響を与えている可能性が示唆された。 次に、(2)について、過冷却解消時の凍結は熱力学的平衡状態における凝固点での凍結よりはるかに速いため、熱水分移動モデルの構築のために過冷却解消時の相変化の速度を明らかにする必要があった。そこで、DSCを様々な温度・水分条件下で行い、過冷却解消時の材料内の含氷率の増加速度と温度・水分条件との対応を検討し、凍結速度のモデルを作成した。また、熱電対により凍結融解過程の材料内の温度分布を詳細に測定した。凍結速度モデルを用いて過冷却を考慮した熱水分移動解析モデルを構築し、凍結融解実験に対応する数値解析を行うことで、モデルの妥当性を検証した。その結果から、構築した熱水分移動モデルは過冷却解消過程の材料内の温度上昇を非常によく再現できることを示した。