Updated on 2025/05/30

写真a

 
Kawaai Keiyu
 
Organization
Graduate School of Science and Engineering (Engineering) Major of Science and Engineering Civil and Environmental Engineering Professor
Title
Professor
Contact information
メールアドレス
External link

Degree

  • Ph.D. ( Supervisor: Prof. Ong Khim Chye, Gary, National University of Singapore, External examiner: Prof. Paulo J. M. Monteiro, University of California, Berkeley )

Research Interests

  • 酸素透過

  • 防錆性能

  • コンクリート工学

  • 腐食

  • Self-healing

  • 物質輸送

  • 電気化学

  • 電気抵抗トモグラフィ

  • Corrosion

  • Infrastructure Materials

  • 社会インフラ材料学

  • 自己治癒

Research Areas

  • Social Infrastructure (Civil Engineering, Architecture, Disaster Prevention) / Civil engineering material, execution and construction management  / コンクリート工学,社会インフラ材料学

Education

  • National University of Singapore   Civil and Environmental Engineering

    2009.8 - 2013.9

      More details

  • 東京工業大学 国際開発工学専攻

    2004.4 - 2006.3

      More details

  • 東京工業大学 開発システム工学科土木コース

    2000.4 - 2004.3

      More details

Research History

  • Ehime University   Graduate School of Science and Engineering Engineering for Production and Environment   Professor

    2024.10

      More details

  • 愛媛大学工学部附属 社会基盤iセンシングセンター 副センター長

    2019.12

      More details

  • Ehime University   Graduate School of Science and Engineering, Engineering for Production and Environment   Associate Professor

    2019.4 - 2024.9

      More details

  • 京都大学インフラ先端技術共同研究講座   招聘研究員

    2016.10 - 2019.3

      More details

  • Ehime University   Graduate School of Science and Engineering, Engineering for Production and Environment

    2016.10 - 2019.3

      More details

  • Delft University of Technology   Civil and Environmental Engineering   Visiting Researcher

    2015.6 - 2015.12

      More details

  • Ehime University   Graduate School of Science and Engineering, Engineering for Production and Environment   Assistant Professor

    2013.10 - 2016.9

      More details

  • National University of Singapore   Civil and Environmental Engineering   Research Engineer

    2013.7 - 2013.9

      More details

  • 千代田化工建設   シビル設計センター

    2006.4 - 2009.7

      More details

▼display all

Professional Memberships

Committee Memberships

  • 愛媛県生コンクリート品質管理監査会議   議長  

    2024.4   

      More details

  • 日本コンクリート工学会   JCI-TA241A コンクリート用自己治癒材の性能評価と実環境での適用に関する研究委員会 委員長  

    2024.4   

      More details

    Committee type:Academic society

    researchmap

  • 土木学会   調査研究部門 土木学会論文編集委員会コンクリート工学編集小委員会(51小委員会)委員  

    2023.6   

      More details

    Committee type:Academic society

    researchmap

  • 日本コンクリート工学会   JCI創立60周年記念事業実行委員会 委員  

    2023.6   

      More details

    Committee type:Academic society

    researchmap

  • 日本コンクリート工学会   JCI-TC235F コンクリート用自己治癒材の効果とその評価方法に関するFS委員会 委員長  

    2023.4 - 2024.3   

      More details

    Committee type:Academic society

    researchmap

  •   日本コンクリート工学会 年次大会2024(松山)実行委員会 副委員長  

    2023.1 - 2024.6   

      More details

    Committee type:Academic society

    researchmap

  • ISO/TC156/ WG15委員会   委員  

    2022.8   

      More details

    Committee type:Academic society

    researchmap

  •   土木学会四国支部 副幹事長  

    2021.6 - 2022.5   

      More details

    Committee type:Academic society

    researchmap

  • 日本コンクリート工学会   実構造物の劣化予測における学術研究の役割とその成果の活用に関する研究委員会 委員  

    2020.4 - 2022.10   

      More details

    Committee type:Academic society

    researchmap

  • 日本コンクリート工学会四国支部   材料分離が生じたコンクリート中の鉄筋腐食性状の評価委員会 委員長  

    2020.4 - 2022.3   

      More details

    Committee type:Academic society

    researchmap

  • 土木学会   インフラメンテナンス総合委員会 知の体系化小委員会 委員  

    2020.3   

      More details

    Committee type:Academic society

    researchmap

  •   四国地域橋梁管理委員会 委員  

    2019.5   

      More details

    Committee type:Municipal

    researchmap

  •   愛媛県建設工事総合評価審査委員会 委員  

    2019.5   

      More details

    Committee type:Municipal

    researchmap

  • 日本コンクリート工学会   コンクリート工学編集委員会 委員  

    2018.4 - 2020.3   

      More details

    Committee type:Academic society

    researchmap

  • RILEM   TC 269 member Damage assessment in Consideration of Repair/ Retrofit-Recovery in Concrete and Masonry Structures by Means of Innovative NDT  

    2017.10 - 2019.9   

      More details

    Committee type:Academic society

    researchmap

  • 日本コンクリート工学会   コンクリートのひび割れ調査,補修・補強指針普及委員会 幹事  

    2017.7   

      More details

    Committee type:Academic society

    researchmap

  • 日本コンクリート工学会   情報コミュニケーション委員会 委員  

    2016.12 - 2018.4   

      More details

    Committee type:Academic society

    researchmap

  • 電気化学的手法を活用した実効的 維持管理手法の確立に関する研究委員会   委員  

    2016.4 - 2018.4   

      More details

    Committee type:Academic society

    researchmap

  • 非破壊試験によるコンクリートに生じた ひび割れの補修評価方法の確立に関する 研究委員会   幹事  

    2016.4 - 2018.4   

      More details

    Committee type:Academic society

    researchmap

  • 四国のコンクリート構造物インフラドックの 実現に向けた調査研究委員会   委員  

    2015.4 - 2017.3   

      More details

    Committee type:Academic society

    researchmap

  •   愛媛県生コンクリート品質管理監査会議 副議長  

    2014.4 - 2024.3   

      More details

    Committee type:Academic society

    researchmap

  • 各種混和材料のコンクリートへの積極利用 による高性能の付与に関する研究委員会   委員  

    2014.4 - 2016.3   

      More details

    Committee type:Academic society

    researchmap

  • 塩害劣化を受けたコンクリート構造物の 耐荷力評価委員会   委員  

    2013.11 - 2015.3   

      More details

    Committee type:Academic society

    researchmap

▼display all

Papers

  • Threshold Value of Chloride Ion Concentration on Corrosion of Steel Bar in PAE-Based Polymer Cement Mortar Reviewed

    Kandai Fujishima, Keiyu Kawaai, Makoto Okubo

    fib SYMPOSIUM ReConStruct   2024.11

     More details

    Authorship:Corresponding author   Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Corrosion Resistance of Self-Healing Concrete Using Alkaliphilic Bacteria Reviewed

    Nami Ishizaki Keiyu Kawaai, Takahiro Nishida

    fib SYMPOSIUM ReConStruct   2024.11

     More details

    Authorship:Corresponding author   Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • 納豆菌と生分解性プラスチックを混合したモルタルの自己治癒効果に関する実験的検討 Reviewed

    西田孝弘, 河合慶有, 林俊斉, 中村孝道

    コンクリート構造物の補修,補強,アップグレード論文報告集   24   789 - 794   2024.10

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • Experimental Investigation of Self-Healing Effect of Mortar Mixed with Bacillus Subtilis and Biodegradable Plastic

    Takahiro Nishida, Keiyu Kawaai

    9th International Conference on Self-Healing Materials   2024.6

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • 微生物代謝を活用したコンクリートの基礎的物性の把握 Reviewed

    林俊斉, 齋藤淳, 河合慶有, 西田孝弘

    コンクリート工学年次論文集   46 ( 1 )   1291 - 1296   2024.6

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • PAE系PCMの鉄筋腐食発生限界塩化物イオン濃度に関する研究

    大久保誠, 河合慶有, 藤島幹大, 東山浩士

    コンクリート工学年次論文集   46 ( 1 )   535 - 540   2024.6

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • Numerical Model of Macro-cell Corrosion Controlled by Oxygen-Diffusion in Concrete Reviewed

    Shun Kusakabe, Keiyu Kawaai, Takahiro Nishida, Isao Ujike

    Conference: Proceedings of the Thirteenth International Conference on Geotechnique, Construction Materials & Environment   13   565 - 570   2023.11

     More details

    Authorship:Last author, Corresponding author   Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Investigation of cathodic polarization characteristics of steel bars in mortar mixed with green tea leaves

    Takahiro Nishida Keiyu Kawaai

    14th ISAJ Annual Symposium on Integrated Science for A Sustainable Society   2023.11

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • QUALITY EVALUATION ON THE SIDE WALL OF BOX CULVERT BASED ON AIR PERMEABILITY TESTS Reviewed

    Haruto Nakagawa, Isao Ujike, Keiyu Kawaai

    Conference: Proceedings of the Thirteenth International Conference on Geotechnique, Construction Materials & Environment   13   560 - 564   2023.11

     More details

    Authorship:Last author, Corresponding author   Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • AI Assisted Cause Estimation of Cracking in Concrete Based on Standard Investigation Reviewed

    Daiki Chikahara, Keiyu Kawaai, Takahiro Nishida, Isao Ujike

    Conference: Proceedings of the Thirteenth International Conference on Geotechnique, Construction Materials & Environment   13   551 - 555   2023.11

     More details

    Authorship:Last author, Corresponding author   Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • EFFECT OF INITIAL CURING ON CRACKING RESISTANCE AGAINST DRYING SHRINKAGE IN PCM SPECIMENS Reviewed

    Kandai Fujishima, Keiyu Kawaai, Isao Ujike

    Conference: Proceedings of the Thirteenth International Conference on Geotechnique, Construction Materials & Environment   13   556 - 559   2023.11

     More details

    Authorship:Last author, Corresponding author   Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Nondestructive Testing for Evaluation of Seel Coated with Heavy Duty Coating Reviewed

    Takahiro Nishida, Keiyu Kawaai

    Conference: Proceedings of 2023 International Conference on Unmanned System Application- Geoinformatics, Agriculture, Manufacturing & Environment   2023.7

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Self-healing Concrete Using Bacillus Subtilis and Biodegradable Plastic for Crack Repair Reviewed

    Keiyu Kawaai, Takahiro Nishida

    Conference: Proceedings of 2023 International Conference on Unmanned System Application- Geoinformatics, Agriculture, Manufacturing & Environment   2023.7

     More details

    Authorship:Lead author, Last author, Corresponding author   Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Non-destructive evaluation for voids under airport pavement concrete in-situ Reviewed

    T. Nishida, F. Izu, Y. Kobayashi, M. Aizawa, K. Kawaai

    Life-Cycle of Structures and Infrastructure Systems   3086 - 3093   2023.6

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:CRC Press  

    DOI: 10.1201/9781003323020-376

    researchmap

  • Numerical evaluation on electrical resistivity of hardened cement paste using 3D pore model based on X-ray micro-CT images Reviewed

    K. Kawaai, T. Nishida

    Life-Cycle of Structures and Infrastructure Systems   3033 - 3040   2023.6

     More details

    Authorship:Lead author, Last author, Corresponding author   Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:CRC Press  

    DOI: 10.1201/9781003323020-369

    researchmap

  • Activation Energies of Chloride Induced Corrosion of Steel in Concrete Reviewed

    Takahiro Nishida, Keiyu Kawaai, Nobuaki Otsuki

    GEOMATE2022   2022.11

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Corrosion of Underground Steel between Soil and Clay and Its Prevention Reviewed

    Keiyu Kawaai, Takahiro Nishida

    GEOMATE2022   2022.11

     More details

    Authorship:Lead author, Last author, Corresponding author   Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • カソード分極試験における鋼材周囲の酸素濃度の変動と律速条件の関係 Reviewed

    平城清志, 河合慶有, 西田孝弘, 氏家勲

    コンクリート構造物の補修,補強,アップグレード論文報告集   22   2022.10

     More details

    Authorship:Corresponding author   Language:Japanese   Publishing type:Research paper (conference, symposium, etc.)  

    researchmap

  • 相対湿度の上昇に伴う水・酸素の供給が中性化よるマクロセル腐食に及ぼす影響

    深川 大輔, 河合 慶有, 西田 孝弘, 氏家 勲

    コンクリート構造物の補修,補強,アップグレード論文報告集   22   2022.10

     More details

    Authorship:Corresponding author   Language:Japanese   Publishing type:Research paper (conference, symposium, etc.)  

    researchmap

  • Assessment of water absorption in concrete member by electrical resistance tomography Reviewed

    K.Kawaai, T. Nishida

    Proceedings of 11th International Conference on Bridge Maintenance, Safety and Management   1560 - 1566   2022.7

     More details

    Authorship:Lead author   Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Application of bio-based materials to crack and patch repair methods in concrete Reviewed

    K.Kawaai, T.Nishida, A.Saito, T.Hayashi

    Construction and Building Materials   340 ( 7 )   127718   2022.7

     More details

    Authorship:Lead author, Last author, Corresponding author   Language:English   Publishing type:Research paper (scientific journal)  

    DOI: 10.1016/j.conbuildmat.2022.127718

    researchmap

  • Crack detection inside concrete based on specific resistivity monitoring Reviewed

    T. Nishida, K. Kawaai

    Proceedings of 11th International Conference on Bridge Maintenance, Safety and Management   1553 - 1559   2022.7

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Reliability of Non-Steady-State Electrophoretic Migration Test Reviewed

    Hiroshi Minagawa, Eisuke Nakamura, Keiyu Kawaai, Shin-ichi Miyazato, Yoshitaka Kato, Toshinobu Yamaguchi

    ACI Materials Journal   119 ( 3 )   223 - 233   2022.5

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    researchmap

  • 締固めを必要とする高流動コンクリートの実大寸法PC桁内での硬化後の品質について

    氏家勲, 河金甲, 河合慶有

    コンクリート工学年次論文集(CD-ROM)   44   2022

  • 鋼材腐食抑制のための酸素低減型混和材の開発 Invited Reviewed

    西田孝弘, 河合慶有, 齋藤淳, 大即信明

    コンクリート構造物の補修,補強,アップグレード論文報告集   2021.10

     More details

    Language:Japanese   Publishing type:Research paper (conference, symposium, etc.)  

    researchmap

  • Reduction Of Dissolved Oxygen In Minimizing Corrosion Reviewed

    VENTANILLA, Mary Grace, ONGPENG, Jason, NISHIDA, Takahiro, KAWAAI, Keiyu

    33   624 - 630   2021.9

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • INFLUENCING FACTORS AFFECTING SELF-HEALING EFFICIENCY IN CEMENTITIOUS MIXTURES Reviewed

    Keiyu KAWAAI, Masahiko IDE

    Cement Science and Concrete Technology   74 ( 1 )   294 - 301   2021.3

     More details

    Authorship:Lead author, Corresponding author   Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Japan Cement Association  

    DOI: 10.14250/cement.74.294

    researchmap

  • Effect of copper slag fine aggregate on corrosion processes and behavior in reinforced concrete prism specimen

    Nevy Sandra, Keiyu Kawaai, Isao Ujike

    Construction and Building Materials   271   2021.2

     More details

    Publishing type:Research paper (scientific journal)  

    © 2020 Elsevier Ltd This paper reports the result of experimental on the resistance to chloride diffusion and steel corrosion of concrete mixtures. A series of tests were performed to investigate the effect of copper slag as partial replacement of fine aggregate on corrosion processes and behavior in prism specimens. Chloride migration tests in steady-state were executed at the age of 28 and 91 days in accordance with Japan Society of Civil Engineers (JSCE) G571-2003 to determine the diffusion coefficient of chloride ions permeated through concrete specimens. In addition, some electrochemical tests were carried out through the repeated wet and dry (NaCl 10%) cycles up to 1 year to examines the probability of corrosion of steel bars in concrete, corrosion current density, and the rate of oxygen permeability. Based on the chloride migration test, which was obtained from the cumulative increase of chloride ion concentration, the results indicate that concrete with a longer curing period achieved lower chloride-ion concentration, thus suggesting that there is an increase in the resistance of concrete against chloride attack. The chloride penetration depth and distribution of chloride content in CUS prism specimens after exposure to wet and dry cycles for one year are almost similar to those of the OPC specimens. Thus, the durability performance of CUS concretes with respect to the resistance against chloride ingress was comparable to that of OPC concrete. Besides that, it is generally recognized that the incorporation of fly ash in blended cement by its the pozzolanic reaction of fly ash improves concrete protection against chloride-induced corrosion of steel bars by reducing its diffusivity and the rate of oxygen permeability.

    DOI: 10.1016/j.conbuildmat.2020.121909

    Scopus

    researchmap

  • 自由落下高さが異なる締固めを必要とする高流動コンクリートの硬化後の品質に関する検討

    氏家勲, 河金甲, 河合慶有, 蔦川昌希

    コンクリート工学年次論文集(CD-ROM)   43   2021

  • Effect of Crack Repair by Bio-Based Materials Using Alginate and Bacillus Subtilis under Wet and Dry Environment Part-I Reviewed

    K. Kawaai, T. Nishida, A. Saito

    XV International Conference on Durability of Building Materials and Components. eBook of Proceedings   2020.10

     More details

    Authorship:Lead author   Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:CIMNE  

    DOI: 10.23967/dbmc.2020.052

    researchmap

  • Effect of Crack Repair by Bio-Based Materials Using Alginate and Bacillus Subtilis under Wet and Dry Environment Part-II Reviewed

    T. Nishida, K. Kawaai, A. Saito

    XV International Conference on Durability of Building Materials and Components. eBook of Proceedings   2020.10

     More details

    Authorship:Last author   Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:CIMNE  

    DOI: 10.23967/dbmc.2020.053

    researchmap

  • EFFECT OF DEGREE OF WATER SATURATION ON OXYGEN PERMEABILITY IN MORTAR SPECIMENS MIXED WITH AEROBIC MICROORGANISM (accepted) Reviewed

    S. Sugitani, K. Kawaai, I. Ujike

    2020.10

     More details

    Authorship:Corresponding author   Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Influence of copper slag on corrosion behavior of horizontal steel bars in reinforced concrete column specimen due to Chloride-induced corrosion Reviewed

    Nevy Sandra, Keiyu Kawaai, Isao Ujike

    Construction and Building Materials   255   2020.9

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    © 2020 Elsevier Ltd Deterioration due to chloride penetration has been regarded as the major problem among the factors leading to a decrease in the durability of reinforced concrete (RC). Corrosion of steel bars in concrete propagates in the presence of water and oxygen by electro-chemical reactions. In recent years, the use of industrial by-products as construction materials has been promoted since it reduces pollutant waste and beneficial in construction works toward sustainable development. Copper slag fine aggregate (CUS) is an industrial by-product produced through the process of manufacturing copper. The aim of this study is to investigate the effects of CUS on the ingress of corrosive substances, including chloride ions and water, including dissolved oxygen associated with corrosion behavior and processes of horizontal steel bars in the reinforced concrete prototype specimen. A detailed analysis was carried out on the heterogeneity in cover concrete and integrity of horizontal steel bars due to bleeding water in concrete mixtures with a partial replacement of CUS and fly ash (FA) and ordinary Portland cement (OPC) as a control specimen. In this study, it is assumed that the deterioration of concrete structures results from chloride ion penetration in the sea. Chloride-induced corrosion through the wet and dry cycles are examined with respect to chloride ion concentrations and some parameters related to electro-chemical measurements. The results show that the partial replacement of fine aggregate with CUS (30 vol%) in reinforced concrete column specimens led to a lower rate of oxygen permeability on the cathodic reactions, which could be illustrated by changes of cathodic polarization properties in column specimens. Although macrocell corrosion is partly pronounced in CUS concrete due to cracking caused by segregation, the microcell corrosion current density observed in CUS concrete specimens is generally less severe compared to those observed in OPC concrete specimens. Based on the results obtained by XRD analysis, the addition of CUS in concrete mixtures as a sand replacement does not register new peaks but increases in peak intensity. The result indicates that CUS replacement does not affect the composition of minerals of concrete mixtures tested, and thus, it is evidently compatible with OPC mixtures. This beneficial effect of the addition of copper slag fine aggregate could contribute to good durability performance in concrete as a solution to the environmental problem of disposal industrial waste, and copper slag concrete has a wide application in the structures constructed in a marine environment.

    DOI: 10.1016/j.conbuildmat.2020.119265

    Scopus

    researchmap

  • コンクリートの塩化物イオン拡散係数を求めるための非定常法電気泳動試験に関するラウンドロビン・テスト Reviewed

    皆川 浩, 中村 英佑, 河合 慶有, 宮里 心一, 加藤 佳孝, 山口 明伸

    コンクリートの性能評価試験の合理化・省力化に関するシンポジウム JCI-C97   305 - 310   2020.9

     More details

    Language:Japanese   Publishing type:Research paper (conference, symposium, etc.)  

    researchmap

  • コンクリート面部材における透気係数の分布性状に関する検討 Reviewed

    山川莉希, 氏家勲, 河合慶有, 山田純平

    コンクリート工学年次論文集   42 ( 1 )   1516 - 1521   2020.7

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • Effects of bleeding on corrosion of horizontal steel bars in reinforced concrete column specimen

    Nevy Sandra, Keiyu Kawaai, Isao Ujike, Ippei Nakai, Willick Nsama

    IOP Conference Series: Materials Science and Engineering   620 ( 1 )   2019.11

     More details

    Publishing type:Research paper (international conference proceedings)  

    © 2019 IOP Publishing Ltd. The durability of reinforced concrete proved to be predominantly controlled by the resistance against ingress of harmful substances including chloride ions, carbon dioxide, and moisture. The corrosion of steel bars taking place especially in a marine environment was likely to be severe, which depends on the availability of oxygen and moisture consumed by cathodic reactions. This study aims to investigate the effects of bleeding on the corrosion of horizontal steel bars placed in reinforced concrete column specimens. This was examined through electro-chemical tests including the half-cell potential, polarization resistance, and corrosion current density carried out using specimens in which corrosion was induced via dry and wet (NaCl 10%) cycles. The presence or absence of copper slag fine aggregate and fly ash replacement were taken up as experimental factors. The results suggested that the corrosion of horizontal steel bars in the upper part of the column concrete specimen was adversely affected even for the case of OPC specimens with relatively lower bleeding water. This was attributed to less resistance against the ingress of corrosive substances especially in those locations. In the case of fly ash mixtures, the corrosion resistance was significantly improved owing to lower oxygen permeability measured via cathodic polarization technique.

    DOI: 10.1088/1757-899X/620/1/012058

    Scopus

    researchmap

  • Corrosion resistance of steel bars in mortar mixtures mixed with organic matter, microbial or other

    K. Kawaai, T. Nishida, A. Saito, I. Ujike, S. Fujioka

    Cement and Concrete Research   124   2019.10

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    © 2019 Elsevier Ltd Dissolved oxygen in pore solution is often a controlling factor determining the rate of corrosion processes of steel bars in concrete. This study reports on corrosion resistance and polarization properties of steel bars in mortar specimen mixed with aerobic microorganisms. The properties are essentially associated with the permeability of dissolved oxygen in pore solution. This could be affected via metabolic activities of aerobic Bacillus subtilis natto mixed in hardened mortar specimens. Mortar specimens with segmented steel bars were prepared using culture solution as a partial replacement of mixing water. The mortar specimens cast with a w/c ratio of 0.50 were cracked by 4-point bending test and then they were exposed to dry (4 days) and wet (3 days) cycles using tap water containing 10% NaCl in order to accelerate corrosion especially at cracked parts. Electro-chemical measurements were carried out to examine the corrosion processes by AC impedance method, half-cell potential measurements, and macrocell corrosion measurements using zero-resistance ammeters. Cathodic polarization curves were measured at the ages of 28 and 91 days before and after the specimens were exposed to chloride-induced corrosion tests through dry and wet cycles. The results indicate that the rate of oxygen permeability inferred based on limiting current density is substantially smaller in the case of mortar specimens mixed with the bacillus subtilis natto. This can be explained by the fact that the dissolved oxygen is consumed by the oxidation of organic matter, a process initially catalyzed by Bacillus subtilis natto present in hardened mortar specimen during the monitoring periods. Based on the results obtained, the addition of culture solution containing Bacillus subtilis natto reacting with dissolved oxygen resulted in higher resistance against corrosion processes, which was confirmed by the results of half-cell potential and microcell and macrocell corrosion current density. There is a strong possibility that the reduced dissolved oxygen in pore solution through the aerobic processes could enhance the corrosion resistance in cracked mortar specimens.

    DOI: 10.1016/j.cemconres.2019.105822

    Scopus

    researchmap

  • 柱供試体に埋設した水平鉄筋の腐食性状に与える酸素透過の影響 Reviewed

    河合 慶有, 氏家 勲

    コンクリート工学年次論文集   2019.7

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • Effects of bleeding on the corrosion of horizontal steel bars in reinforced concrete column specimens Reviewed

    Nevy Sandra, Keiyu Kawaai, Isao Ujike, Ippei Nakai, Willick Nsama

    International Journal of Technology   10 ( 4 )   741 - 752   2019.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    © IJTech 2019. The durability of reinforced concrete has proven to be predominantly influenced by its resistance against the ingress of harmful substances such as chloride ions, carbon dioxide and moisture. The corrosion of steel bars which occurs especially in marine environments is likely to be severe, depending on the availability of oxygen and the moisture consumed by cathodic reactions. This study aims to investigate the effects of bleeding on the corrosion of horizontal steel bars placed in reinforced concrete column specimens. The issue was examined through electro-chemical tests, including half-cell potential, polarization resistance and corrosion current density, conducted using specimens in which corrosion was induced via dry and wet (NaCl 10%) cycles. The presence or absence of copper slag fine aggregate and fly ash replacement was employed as an experimental parameter. The results suggest that the corrosion of horizontal steel bars in the upper part of the column concrete specimens was adversely affected, even in the case of OPC specimens with relatively lower bleeding water. This was attributed to lower resistance against the ingress of corrosive substances, especially in such locations. In the case of fly ash mixtures, resistance to corrosion was significantly improved owing to lower oxygen permeability of less than 1.0×10-11mol/cm2/sec, measured via the cathodic polarization technique. The replacement of fly ash is effective in facilitating more uniform quality in the column specimens due to a lower level of bleeding water and higher resistance to segregation and pozzolanic reactions.

    DOI: 10.14716/ijtech.v10i4.2503

    Scopus

    researchmap

  • Application of bio-based material for concrete repair: case study leakage on parallel concrete slab Reviewed

    Prima Yane Putri, Isao Ujike, Keiyu Kawaai

    MATEC Web of Conferences 258:01013   2019.1

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • -

    2019

     More details

    Language:Japanese   Publishing type:Research paper (conference, symposium, etc.)  

    researchmap

  • Effect of oxygen permeability on corrosion properties in mortar specimens mixed with bacillus subtilis Reviewed

    Saaya Sugitani, Keiyu Kawaai, Isao Ujike

    MATEC Web Conf. 7th International Conference on Concrete Repair   289   2019

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Corrosion Current Density of Macrocell of Horizontal Steel Bars in Reinforced Concrete Column Specimen Reviewed

    N. Sandra, K. Kawaai, I. Ujike

    International Journal of Geomate   16 ( 54 )   123 - 128   2019

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    researchmap

  • Electrical Resistance Tomography for Assessing Water Movement in Cracked Cementitious Mixtures

    Keiyu Kawaai, Isao Ujike

    MATEC Web of Conferences   199   2018.10

     More details

    Publishing type:Research paper (international conference proceedings)  

    © 2018 The Authors, published by EDP Sciences. Electrical resistance tomography (ERT) has been studied for visualizing variations of conductivity in concrete specimens. In recent years, unsaturated water flow through pores formed in concrete has been intensively examined though ERT systems to visualize the permeation front that gradually changes with elapsed time. This study examines water movement through internal cracks which are typically not observed on the surface of mortar or concrete specimens via ERT systems. The results indicate the gradual increase of saturated region owing to the ingress of water through cracked surface up to 120 hours. And, the region with higher conductivity estimated in uncracked parts is evidently in good agreement with higher moisture content measured by moisture meter on the split surface. In addition, the presence of crack in concrete specimen subjected to water ingress is clearly visualized via ERT images owing to rapid water movement in cracked zones. This study has provided the important insight that the ingress and the movement of water through pores and cracks formed in cementitious mixtures could be assessed via electrical measurements.

    DOI: 10.1051/matecconf/201819911016

    Scopus

    researchmap

  • ALGINATE-BACILLUS SUBTILIS BASED REPAIR MATERIALS FOR SEALING CRACKS IN CONCRETE Reviewed

    Masahiko Ide, Keiyuu Kawaai, Isao Ujike

    2018.10

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • EFFECT OF INITIAL CURING ON CORROSION BEHEAVIOR OF STEEL BARS IN FA CONCRETE UNDER DRY AND WET ACTIONS Reviewed

    Wakako Sugino, Keiyuu Kawaai, Isao Ujike

    2018.10

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Influence of bleeding on modification of pore structure and carbonation-induced corrosion formation Reviewed

    Willick Nsama, Isao Ujike, Keiyu Kawaai, Yuto Kubo, Nevy Sandra

    4th International Conference on Service Life Design for Infrastructures   2018.8

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Abundance and size of microplastics in a coastal sea: Comparison among bottom sediment, beach sediment, and surface water Reviewed

    Nao Sagawa, Keiyu Kawaai, Hirofumi Hinata

    Marine Pollution Bulletin   133   532 - 542   2018.8

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    © 2018 Elsevier Ltd Microplastics have adverse effects on marine life. This study examined the abundance and size of microplastics as well as their polymer types in the surface water and the bottom and beach sediments of Hiroshima Bay. The fragmentation process and sinking factors of foamed polystyrene (FPS) microplastics were also examined. Serious FPS pollution spread out not only in the beach sediments but also in the bottom sediments. The average size of FPS particles in the bottom sediments was significantly smaller than that of beached FPS particles. Field emission scanning electron microscopy images suggest that large amounts of microsized or nanosized FPS fragments are likely to be generated from the margins of beached FPS microplastics. X-ray computed tomography images show that FPS microplastics from the bottom sediments had tunnel-like structures inside the particle. Based on these images, FPS microplastics in the bottom sediments were susceptible to biofouling and soil deposition.

    DOI: 10.1016/j.marpolbul.2018.05.036

    Scopus

    PubMed

    researchmap

  • CORROSION PROPERTIES OF HORIZONTAL STEEL BARS IN CONCRETE COLUMN SPECIMENS CAST WITH COPPER SLAG FINE AGGREGATE Reviewed

    N. Sandra, K. Kawaai, I. Ujike

    4th International Conference on Service Life Design for Infrastructures   2018.8

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • APPLICABILITY OF BIO-BASED MATERIALS TO REPAIR WATER LEAKAGE OF CONCRETE Reviewed

    Prima Yane PUTRI, Isao UJIKE, Keiyu KAWAAI

    40th Japan Concrete Institute Annual Convention   2018.7

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    researchmap

  • 非破壊試験によるコンクリートに生じたひび割れの補修評価方法の確立に関する研究委員会

    塩谷智基, 西田孝弘, 河合慶有, 濱崎仁, 渡辺健, 今本啓一

    コンクリート工学年次論文集(CD-ROM)   40   ROMBUNNO.0003   2018.6

     More details

    Language:Japanese  

    J-GLOBAL

    researchmap

  • CATHODIC POLARIZATION PROPERTIES OF STEEL BARS IN CONCRETE MIXED WITH AEROBIC MICROORGANISM Reviewed

    K. Kawaai, I. Ujike, S. Fujioka, T. Nishida, A. Saito

    Final Conference of RILEM TC 253-MCI   2018.6

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Restrained early age shrinkage at the vertical interface between fresh cementitious mixtures and hardened substrates Part-II Reviewed

    K. Kawaai, O.K.C. Gary

    International Journal of Engineering Research and Applications   2018

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    researchmap

  • Restrained early age shrinkage at the vertical interface between fresh cementitious mixtures and hardened substrates Part-I Reviewed

    K.Kawaai, O.K.C. Gary

    International Journal of Engineering Research and Applications   2018

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    researchmap

  • ブリーディングに起因する表層品質の相違に対する透気係数および含水率の関係に基づく評価方法 Reviewed

    久保 勇登, 河合 慶有, 氏家 勲

    コンクリート構造物の補修,補強,アップグレード論文報告集   2017.10

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • INFLUENCE OF BLEEDING ON VARIATIONS OF PERMEABILITY IN CONCRETE COLUMN SPECIMENS Reviewed

    KAWAAI Keiyu

    2017.8

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Cracking resistance for drying shrinkage of concrete mixed with copper/manganese slag fine aggregates and fly ash Reviewed

    Keiyu Kawaai, Isao Ujike, Mutsumi Mizukoshi

    Zairyo/Journal of the Society of Materials Science, Japan   66 ( 8 )   615 - 620   2017.8

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Society of Materials Science Japan  

    © 2017 The Society of Materials Science, Japan. Drying shrinkage is inevitable in concrete mixtures when exposed to dry environment. This is not only dependent on hardened cement paste comprising the types of cement and water content, but the properties of aggregates including water absorption capacity and elastic modulus. Generally materials design with respect to enhance the resistance against drying shrinkage cracking aims at higher strength development and reduced drying shrinkage, which can be obtained by lower water content and the proper use of cement and mineral admixtures in concrete mixtures and the use of aggregates with lower water absorption capacity and higher elastic modulus. This study examined the resistance against drying shrinkage cracking in concrete mixtures mixed with two types of slag fine aggregates (copper and manganese slag) and fly ash, which was investigated using restrained reinforced concrete specimens. The results showed that the cracking resistance was enhanced in concrete mixtures mixed with copper slag fine aggregate and fly ash, which could be explained by the fact that the restrained stress was partially relaxed during the early stages of exposure to dry environment. In addition, fresh properties including slump, air content and bleeding rate were also tested for practical application.

    DOI: 10.2472/jsms.66.615

    Scopus

    researchmap

  • Effect of initial curing on ingress of corrosive substances and corrosion resistance in fly ash concrete Reviewed

    Keiyu Kawaai, Isao Ujike

    Zairyo/Journal of the Society of Materials Science, Japan   66 ( 8 )   608 - 614   2017.8

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Society of Materials Science Japan  

    © 2017 The Society of Materials Science, Japan. This study reports on the effect of initial curing on corrosion resistance of fly ash (FA) concretes, which was examined through chloride-induced corrosion tests induced by dry and wet cycles. Detailed analysis was carried out on the resistance against ingress of harmful corrosive substances assessed via air permeability tests and cathodic polarization measurements in determining oxygen permeability on embedded steel bars. They were largely affected by the moisture content, the pore structure including pore volume, size distribution and its connectivity which were examined via mercury intrusion porosimetry. In addition, the results showed that the corrosion resistance was observed to be dependent on the availability of calcium hydroxide consumed via the pozzolanic reactions which could affect the initiation of corrosion in the incubation period and the oxygen permeability on embedded steel bars with wet conditions for the early propagation period. Higher resistance against chloride ingress in the FA concrete could be attributed to denser pore structure formed and relatively lower moisture content in the deeper zones especially when cured under dry environment.

    DOI: 10.2472/jsms.66.608

    Scopus

    researchmap

  • 鉄筋コンクリートの防食電流・電位の変動要因と防食効果 Reviewed

    河合 慶有, 大即 信明, 西田 孝弘

    材料   66 ( 8 )   601 - 607   2017.8

     More details

    Authorship:Lead author   Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • Influencing factors on current distribution and potentials under cathodic protection on steel bars in concrete and effect of protection against corrosion Reviewed

    Keiyu Kawaai, Nobuaki Otsuki, Takahiro Nishida

    Zairyo/Journal of the Society of Materials Science, Japan   66 ( 8 )   601 - 607   2017.8

     More details

    Authorship:Lead author   Language:Japanese   Publishing type:Research paper (scientific journal)   Publisher:Society of Materials Science Japan  

    © 2017 The Society of Materials Science, Japan. Protecting steel bars in concrete against corrosion through the use of cathodic protection system has been successfully used for marine structures as the most effective method in controlling corrosion current taking place in reinforced concrete. DC current flowing into steel bars in concrete is required to be uniformly distributed, which is essential in controlling the corrosion via lowered potentials along the steel bars. The design criteria commonly used for the cathodic protection is a polarization measured on the steel bars which is greater than 0.1V immediately after power supply stops (instant-off). It has been pointed out that the current distribution varies owing to the heterogeneity of composite materials in concrete including moisture distribution and chloride ion concentration, defects typically present in concrete including cold-joint and cracks and the deterioration stages such as incubation and propagation periods. This led to variations observed in the potentials which may result in unsatisfactory protection potentials. In this study, the influence of localized defects and corrosion on the current density and potentials were examined using segmented steel bars embedded in concrete, which was investigated via electro-chemical measurements. Based on findings, a design criteria required for reinforced concrete with defects in the case of chloride-induced corrosion was shown in controlling the potential on the steel bar below -0.85V vs. CSE reference electrode especially during propagation period.

    DOI: 10.2472/jsms.66.601

    Scopus

    researchmap

  • 銅・マンガンスラグ細骨材およびフライアッシュを用いたコンクリートの乾燥収縮ひび割れ抵抗性 Reviewed

    河合 慶有, 氏家 勲, 水越 睦視

    材料   66 ( 8 )   615 - 620   2017.8

     More details

    Authorship:Lead author   Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • 初期養生がフライアッシュコンクリート中の腐食因子の侵入と鉄筋腐食抵抗性に与える影響 Reviewed

    河合 慶有, 氏家 勲

    材料   66 ( 8 )   608 - 614   2017.8

     More details

    Authorship:Lead author   Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • 材料分離に起因する不均質さが水平鉄筋の腐食性状に与える影響 Reviewed

    河合 慶有, 氏家 勲

    コンクリート工学年次論文集   2017.7

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • 製紙スラッジ焼却灰を利用した低炭素コンクリートの性能評価 Reviewed

    木下 尚樹, 氏家 勲, 河合 慶有, 川口 隆, 安原 英明, 長江 俊勝

    Journal of MMIJ   2017.7

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    DOI: 10.2473/journalofmmij.133.132

    researchmap

  • Influence of the type of dry yeast on precipitation rate of calcium carbonate in bio-based repair materials Reviewed

    ICBBM ECOGRAFI

    2017.6

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Alginate capsules encapsulating aerobic and anaerobic microorganism for repairing cracks in concrete Reviewed

    6th International Conference on Self-Healing Materials   2017.6

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • Influence of bleeding on durability of horizontal steel bars in RC column specimen Reviewed

    K. Kawaai, I. Ujike

    Life-Cycle of Engineering Systems: Emphasis on Sustainable Civil Infrastructure - 5th International Symposium on Life-Cycle Engineering, IALCCE 2016   839 - 846   2017

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    © 2017 Taylor & Francis Group, London. This study reports on the influence of bleeding on the durability of reinforced concrete, especially horizontally placed steel bars in RC column specimens. This was examined through the use of insitu air permeability tests and electro-chemical tests. The results showed that air permeability coefficients measured in the upper parts of column specimen were relatively higher when the specimens were dried under room conditions, which was dependent on bleeding rate. Although the durability of horizontal steel bars was aggravated by bleeding in a form of segregation, which was confirmed by larger corrosion current density caused by chloride attack through dry and wet cycles, the adverse effect on the durability of horizontal steel bars was less prominent in fly ash mixtures tested in this study.

    Scopus

    researchmap

  • Study on detection method of defects in coveredconcrete using electrical resistivity measurement Reviewed

    Keiyu Kawaai, Isao Ujike, Hiroshi Okuno

    ISEC 2017 - 9th International Structural Engineering and Construction Conference: Resilient Structures and Sustainable Construction   2017

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    Copyright © 2017 ISEC Press. This study reports on a fundamental study on the investigation of electrical resistivity measurements for detecting internal defects or damages, which aims at developing Electrical Resistance Tomography techniques based on electrical resistivity distribution measured via Wenner method. In particular, this study examined the changes of resistivity upon the presence of damages in the bottom of concrete specimens which mirror internal cracking not visually observed on the concrete surface in typical reinforced concrete structure. For the experimental investigation, ten electrodes comprising stainless steel and electric conductive epoxy were partially embedded on the surface of prism concrete specimen. Then, electrical resistivity was measured via Wenner method using four electrodes selected among the electrodes placed 20 mm apart each other. In addition, analytical investigation simulating the influence of internal damages on current flow and measured voltage or potential was carried out by FEM analysis. As a result, electrical resistivity increased depending on the depth of slits with 1 mm width, which was sawed at the bottom of the specimen. This could be attributed to the influence of the damages on the current flow and equipotential planes, thus suggesting that there is a good possibility that internal damages can be detected based on the changes and the distributions of the electrical resistivity.

    DOI: 10.14455/isec.res.2017.102

    Scopus

    researchmap

  • Influence of different concentration of tris buffer solution on calcium carbonate precipitation in bio-based repair materials Reviewed

    Prima Yane Putri, Keiyu Kawaai, Isao Ujike, Hiroshi Okuno

    International Journal on Advanced Science, Engineering and Information Technology   7 ( 5 )   1879 - 1885   2017

     More details

    Language:English   Publishing type:Research paper (scientific journal)   Publisher:Insight Society  

    This research examined differences in the concentration of Tris buffer solution on calcium carbonate precipitation in biobased repair materials. Four concentrations of Tris buffer solution were chosen based on previous research with initial pH 8.0 and 9.0. Initial experiments demonstrated that the concentration and pH of Tris buffer solution had an influence on the amount of precipitation of calcium carbonate. X-Ray Diffraction (XRD) analysis elucidated the morphological and structural differences of the calcium carbonate crystal, including calcite and vaterite. They are the prominent forms of CaCO3 detected based on results obtained by according to FT-IR analysis. The result further explains the effectiveness of Tris buffer concentration.

    DOI: 10.18517/ijaseit.7.5.3452

    Scopus

    researchmap

  • Enhancement of corrosion resistance in mortar using aerobic bacillus subtilis Reviewed

    K. Kawaai, I. Ujike, P.Y. Putri

    HealCon   2016.11

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • ひび割れ抵抗性試験に対する計算モデルの提案 Reviewed

    石川 雅美, 河合 慶有

    セメント・コンクリート研究討論会 論文報告集   2016.10

     More details

    Language:Japanese   Publishing type:Research paper (conference, symposium, etc.)  

    researchmap

  • イースト菌による微生物代謝を利用したひび割れ補修材のカプセル化

    河合 慶有, 氏家 勲, 奥野 宙

    セメント・コンクリート研究討論会 論文報告集   2016.10

     More details

    Language:Japanese   Publishing type:Research paper (conference, symposium, etc.)  

    researchmap

  • A study on the factors affecting electro-migration characteristic of chloride ion in concrete Reviewed

    ASEA SEC, International Conference

    2016.9

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • コンクリート内部の損傷が電気抵抗率の分布に与える影響 Reviewed

    岡田 辰夫, 河合 慶有, 氏家 勲

    コンクリート工学年次論文集   38   2016.7

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • 自然環境下の表層コンクリートに対する透気試験を用いた耐久性能推定手法の適用可能性 Reviewed

    村上 賢晃, 氏家 勲, 河合 慶有

    コンクリート工学年次論文集   38   2016.7

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • A Novel Method in Enhancing Corrosion Resistance in Concrete Using Aerobic Bacillus Subtilis Reviewed

    K. Kawaai, T. Nishida, A. Saito, I. Ujike

    International Symposium on Concrete and Structures for Next Generation: Ikeda & Otsuki Symposium (IOS 2016)   2016.5

     More details

    Language:English   Publishing type:Research paper (conference, symposium, etc.)  

    researchmap

  • Effect of Temperature on Precipitation Rate of Calcium Carbonate Produced Through Microbial Metabolic Process of Bio Materials Reviewed

    Prima, Y. P, Kawaai, K, Ujike, I

    Journal of Civil Engineering Science and Application   2016

     More details

    Language:English   Publishing type:Research paper (scientific journal)  

    researchmap

  • Some considerations on precipitation rate of calcium carbonate in bio-based materials used for concrete repair Reviewed

    K. Kawaai, I. Ujike, S. Yamamoto, P. Y. Putri

    Concrete Solutions - Proceedings of Concrete Solutions, 6th International Conference on Concrete Repair, 2016   571 - 578   2016

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:CRC PRESS-TAYLOR & FRANCIS GROUP  

    © 2016 Taylor & Francis Group, London. This paper presents some considerations on repair methods using bio-based materials comprising yeast, glucose or sucrose and calcium acetate mixed inTris buffer solution.The investigation revealed that calcium carbonate can precipitate as crystals within 24 hours depending on the concentrations of these materials used in the mixture and pH levels. The results suggested that reaction rate at early stages e.g. 6 hours later and resulting precipitates up to 24 hours after mixing may have a significant effect on the effectiveness of sealing cracks in concrete.

    Web of Science

    Scopus

    researchmap

  • CARBONATION AT VERTICAL INTERFACES FORMED BETWEEN FRESHLY CAST CEMENTITIOUS MIXTURES AND HARDENED CONCRETE SUBSTRATES Reviewed

    K. Kawaai, A. Annapareddy, K.C.G. Ong, C.T. Tam

    40th Conference on Our World Concrete & Structures   1 - 8   2015.8

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • ESTIMATION METHOD FOR DURABILITY PERFORMANCES IN COVER CONCRETE BY IN-SITU AIR PERMEABILITY TESTS Reviewed

    K. Kawaai, I. Ujike

    The Fifth International Conference on Construction Materials: Performance, Innovations and Structural Implications   2015.8

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • 銅スラグ細骨材とフライアッシュを使用した乾燥収縮ひび割れ抑制コンクリートの開発 Reviewed

    仲井一平, 高本直樹, 河合慶有, 氏家勲

    コンクリート工学年次論文集(CD-ROM)   37   ROMBUNNO.1072   2015.6

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    J-GLOBAL

    researchmap

  • 乾湿繰り返し作用を受けるフライアッシュコンクリートの鉄筋腐食性状に及ぼす初期養生および水結合材比の影響 Reviewed

    門屋朱里, 春日翔平, 河合慶有, 氏家勲

    コンクリート工学年次論文集(CD-ROM)   37   ROMBUNNO.1129   2015.6

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    J-GLOBAL

    researchmap

  • 炭酸カルシウムの析出速度及び析出量に及ぼす諸要因に関する研究 Reviewed

    山本沙也, 久保郁貴, 河合慶有, 氏家勲

    コンクリート工学年次論文集(CD-ROM)   37   ROMBUNNO.1259   2015.6

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    J-GLOBAL

    researchmap

  • Effect of curing condition on air permeability coefficient measured by in-situ test method Reviewed

    K. Kawaai, I. Ujike, S. Kunikata, S. Okazaki

    Life-Cycle of Structural Systems: Design, Assessment, Maintenance and Management - Proceedings of the 4th International Symposium on Life-Cycle Civil Engineering, IALCCE 2014   1207 - 1214   2015

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:CRC PRESS-TAYLOR & FRANCIS GROUP  

    © 2015 Taylor & Francis Group, London. This paper presents the investigation on an in-situ assessment technique for durability performances of cover concrete based on the relationship between air permeability coefficients and moisture content. First, an assessment technique for the quality of cover concrete using insitu air permeability tests in conjunction with moisture content measurements was examined. Durability performances of concrete specimens subjected to different curing conditions at an early age were subsequently studied via accelerated tests. Finally, this study exemplified the application of the assessment technique to existing RC structure.

    DOI: 10.1201/b17618-178

    Web of Science

    Scopus

    researchmap

  • Effects of Internal Cracking and Drying Shrinkage on the Corrosion Processes of RC Beam Specimens Reviewed

    K. Kawaai, I. Ujike, I. Nakai

    CONCREEP 2015: Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures - Proceedings of the 10th International Conference on Mechanics and Physics of Creep, Shrinkage, and Durability of Concrete and Concrete Structures   477 - 486   2015

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:AMER SOC CIVIL ENGINEERS  

    © ASCE. Internal cracking tend to arise from the edge of knots present in deformed bars embedded in tension zone of reinforced concrete structure when loaded up to 100 N/mm. This could be further exacerbated by drying shrinkage depending on types of aggregate used in concrete mixtures under dry environment. The objective of this study was to examine the durability performance of internally cracked RC beam specimens cast using aggregate including crushed limestone and sandstone with different absorption capacity obtained in regional resources. Based on accelerated chloride-induced corrosion tests carried out via a cycle of 3-day wet and 11-day dry until the age of 1 year, although corrosion tended to occur severely in the cracked parts with higher chloride content depending on the drying shrinkage of concrete specimens, the results showed that internal cracking could trigger localized corrosion initiated especially at the knots of deformed steel bar.

    DOI: 10.1061/9780784479346.057

    Web of Science

    Scopus

    researchmap

  • SHORT-TERM AND LONG-TERM SOLUTIONS USING FLY ASH FOR SUSTAINABLE DEVELOPMENT IN CONCRETE CONSTRUCTION INDUSTRY Reviewed

    K. Kawaai, I. Ujike, S. Kasuga, H. Miyake

    Proceedings of Workshop on Utilization of Waste Materials, Manila   2014.8

     More details

    Language:English   Publishing type:Research paper (conference, symposium, etc.)  

    researchmap

  • 微生物を利用した補修工法における多析出可能な配合の検討 Reviewed

    久保 郁貴, 矢野元 智也, 氏家 勲, 河合 慶有

    コンクリート工学年次論文集   36 ( 1 )   1948 - 1953   2014.7

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • 現場透気試験によるかぶりコンクリートの耐久性能評価手法の検討 Reviewed

    河合 慶有, 國方 翔太, 氏家 勲

    コンクリート工学年次論文集   36 ( 1 )   2140 - 2145   2014.7

     More details

    Language:Japanese   Publishing type:Research paper (scientific journal)  

    researchmap

  • Influencing factors affecting microbial metabolic processes of bio materials used for leaking repairs Reviewed

    I. Ujike, F. Kubo, K. Kawaai, S. Okazaki

    Concrete Solutions - Proceedings of Concrete Solutions, 5th International Conference on Concrete Repair   127 - 133   2014

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)   Publisher:CRC PRESS-TAYLOR & FRANCIS GROUP  

    This paper presents influencing factors on repair methods using bio grout comprising dry yeast, sucrose and calcium acetate.The investigation reveals that calcium carbonate can precipitate as crystals depending on the concentrations of those materials used in the grout and pH levels. The results suggest that the precipitates can increase even at higher concentrations than materials used, which could be attributed to the proper treatment of pH adjustment. It was found that the precipitates were large enough to seal gaps formed between concrete specimens and the effectiveness in reducing water permeability was also shown. © 2014 Taylor & Francis Group.

    Web of Science

    Scopus

    researchmap

  • DURABILITY DESIGN OF TYPICAL DFD (DESIGN FOR DISASSEMBLY) COMPONENTS FOR A TROPICAL ENVIRONMENT Reviewed

    KEIYU KAWAAI

    National University of Singapore   2013.9

     More details

    Language:English   Publishing type:Doctoral thesis  

    researchmap

  • SIZE-EFFECT OF EARLY AGE SHRINKAGE AT THE INTERFACE BETWEEN FRESH CEMENTITIOUS MIXTURES AND HARDENED CONCRETE SUBSTRATE Reviewed

    K.C.G. Ong, K. Kawaai, C.T. Tam, Sze-Dai Pang

    37rd Our World in Concrete and Structures   309 - 320   2013.8

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • STUDY ON CURRENT DISTRIBUTION AT CONCRETE DEFECTS FOR CATHODIC PROTECTION IN REINFORCED CONCRETE MEMBER INDUCED BY CHLORIDE ATTACK Reviewed

    K. Kawaai, N. Otsuki, K. Matsukawa

    33rd Our World in Concrete and Structures   2008.8

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • PROPOSED DESIGN METHOD OF CATHODIC PROTECTION SYSTEM FOR REINFORCED CONCRETE MEMBER INDUCED BY CHLORIDE ATTACK Reviewed

    K. Kawaai, N. Otsuki, T. Nishida, K. Matsukawa

    31rd Our World in Concrete and Structures   207 - 213   2006.8

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

  • FUNDAMENTAL STUDY ON FACTORS INFLUENCING THE CURRENT DISTRIBUTION OF CATHODIC PROTECTION METHOD FOR REINFORCED CONCRETE

    K. Kawaai, N. Otsuki, T. Nishida, R. Zheng

    Proceedings of the Sixth International Summer Symposium, JSCE   Vol.6   361 - 364   2004

     More details

    Language:English   Publishing type:Research paper (international conference proceedings)  

    researchmap

▼display all

Books

  • コンクリートのひび割れ調査,補修・補強指針-2022年版の概要-

    鎌田敏郎, 今本啓一, 長田光司, 河合慶有( Role: Joint author)

    PC工学会会誌 解説  2023.9 

     More details

  • 生分解性プラスチックを用いたコンクリート用自己治癒材の開発

    河合慶有( Role: Sole author)

    ファインケミカル  2023.3 

     More details

  • 「コンクリートのひび割れ調査,補修・補強指針 2022」の概要とポイント

    今本啓一, 鎌田敏郎, 西田孝弘, 宮里心一, 長田光司, 河合慶有, 網野貴彦, 大即信明( Role: Joint author)

    コンクリートテクノ  2023 

     More details

  • コンクリートのひび割れ調査,補修・補強指針2022

    ( Role: Contributor)

    公益社団法人 日本コンクリート工学会  2022.6 

     More details

  • “はじめて”のインフラメンテナンス講座

    宮里 心一, 石川 裕夏, 今井 努, 臼井 裕喜, 風間 洋, 上原子 晶久, 河合 慶有, 木下 幸治, 櫻庭 浩樹, 出水 享, 蓮池 里菜, 藤田 弘昭( Role: Contributor)

    インフラメンテナンス総合委員会 知の体系化小委員会  2022.5 

     More details

  • 自己治癒材の活用と将来展望ーひび割れ補修と防錆性能ー

    河合慶有( Role: Sole author)

    コンクリート工学  2022.1 

     More details

  • コンクリート中鋼材の腐食抑制のための酸素低減型混和材の開発

    河合慶有, 西田孝弘, 齋藤淳, 大即信明( Role: Contributor)

    コンクリート工学  2021.5 

     More details

  • 生物代謝を利用した高機能コンクリートの開発

    河合慶有, 西田孝弘, 齋藤淳( Role: Contributor)

    月間コンクリートテクノ  2020.10 

     More details

  • 自己修復材料、自己組織化、形状記憶材料の開発と応用事例

    ( Role: Contributor)

    技術情報協会  2020.3 

     More details

  • スマートマテリアル総覧 (自己修復材料編)

    河合 慶有( Role: Contributorコンクリート材料)

    2018.10 

     More details

  • 「非破壊手法を用いたコンクリート構造物の補修評価」に関するシンポジウム委員会報告書

    塩谷智基, 今本啓一, 河合慶有, 西田孝弘, 濱崎仁, 水谷司, 渡辺健, 大野健太郎, 奥出信博, 小椋紀彦, 神田利之, 小林義和, 小室睦江, 鈴木哲也, 西脇智哉, 増井直樹, 松山公年, 渡辺佳彦, 渡部一雄, 大津政康, 高田和法

    2018 

     More details

▼display all

Presentations

  • 茶葉を混合したモルタル中鋼材のカソード分極特性に関する基礎的検討

    西田孝弘, 河合慶有

    セメント技術大会講演要旨(CD-ROM)  2023 

     More details

    Event date: 2023

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • 炭酸水による二酸化炭素のセメント硬化体への固定の検討

    濱岡祥樹, 氏家勲, 河合慶有, 力石傑

    セメント技術大会講演要旨(CD-ROM)  2023 

     More details

    Event date: 2023

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • コンクリート中鋼材の腐食抑制のための酸素低減型混和材の開発 (特集 コンクリート中鋼材の腐食診断と防食・補修の現状と未来) -- (防食・補修技術の現状とこれから)

    河合 慶有, 西田 孝弘, 齋藤 淳, 大即 信明

    コンクリート工学  2021.5  日本コンクリート工学会

     More details

    Event date: 2021.5

    Language:Japanese  

    researchmap

  • フィリピンで産出される副産物を利用した酸素低減型混和材料の探索

    西田孝弘, 河合慶有, 齋藤淳, ONGPENG Jason Maximino C., VANTANILLA Mary Grace

    土木学会年次学術講演会講演概要集(CD-ROM)  2020 

     More details

    Event date: 2020

    researchmap

  • 細菌を活用したコンクリートの性能向上技術の開発のための基礎的検討

    齋藤淳, 中島史暁, 河合慶有, 西田孝弘

    土木学会年次学術講演会講演概要集(CD-ROM)  2018 

     More details

    Event date: 2018

    researchmap

  • 技術者教育について Invited

    河合 慶有

    日本コンクリート工学会四国支部報告会  2017.7 

     More details

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    researchmap

  • ブリーディングが柱供試体の表層品質に与える影響分析

    深川大輔, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会2021  2021.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • ひび割れ中の酸素濃度を対象とした非接触式酸素計測に関する検討

    谷川魁, 高升那々子, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会2021  2021.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • X線CT画像を用いた細孔構造に基づく電気抵抗率の直接計算

    田中碧, 阿部光一郎, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会2021  2021.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • 微生物を用いたひび割れ補修と腐食抑制 Invited

    河合慶有

    独立行政法人日本学術振興会 レジリエントインフラのための次世代建設材料の創成R023委員会  2022.5 

     More details

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    researchmap

  • 酸素低減材を断面修復部に用いたコンクリート中鉄筋の腐食性状

    増原菜美, 杉谷紗理, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会2021  2021.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • 分極特性を考慮したコンクリート中の鉄筋腐食モデルに関する研究

    深川大輔, 杉野和可子, 河合, 慶有 氏家勲

    土木学会四国支部技術研究発表会2020  2020.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • 表層コンクリートの乾燥がERTの表面電位に与える影響

    立松佳祐, 河合慶有, 氏家 勲

    土木学会四国支部技術研究発表会2020  2020.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • フィリピンでの副産物を利用した酸素低減型混和材料の探索

    西田孝弘, 河合慶有, Jason Maximino, C. Ongpeng,Mary Grace Vantanilla

    土木学会全国大会  2020.9 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • カソード分極試験中の鉄筋表面周囲における酸素拡散に関する基礎的研究

    平城清志, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会2021  2021.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • 土木学会 知の体系化小委員会の取り組み

    河合慶有

    地域のインフラメンテナンスの明日を考えるシンポジウム(パネリスト)  2023.1 

     More details

    Language:Japanese   Presentation type:Symposium, workshop panel (nominated)  

    researchmap

  • Bio-based materials: crack repair and enhancement of corrosion resistance Invited

    Keiyu Kawaai

    International Conference on Civil and Mining Engineering (Keynote)  2022.10 

     More details

    Language:English   Presentation type:Oral presentation (keynote)  

    researchmap

  • 水分浸透と酸素透過を対象とした計測技術

    河合慶有

    JCI-TC201A コンクリート構造物の劣化予測における学術研究の役割とその成果の活用に関する研究委員会報告会  2022.9 

     More details

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    researchmap

  • 鉄筋コンクリートに対する適切な電気防食回路の設計に関する基礎的研究

    河合慶有, 大即信明, 西田孝弘, 鄭仁沢

    セメント技術大会講演要旨  2004.4 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • X線CT画像から取得した空隙構造を用いた透気性状の検討

    氏家勲, 柴田真帆, 河合慶有

    土木学会四国支部技術研究発表会  2015.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • バイオグラウトの炭酸カルシウム析出時間に影響を及ぼす要因の検討

    山本沙也, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会  2015.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • 養生条件の違いがフライアッシュコンクリートの中性化に及ぼす影響

    門屋朱里, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会  2015.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • 乾燥収縮量の異なる骨材を使用したRC梁の一定持続載荷下での鉄筋腐食に関する研究

    高本直樹, 菅野啓介, 氏家勲, 河合慶有

    土木学会四国支部技術研究発表会  2014.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • 電着工法におけるひび割れ深部での電着物析出阻害の機構解明およびその改善

    鈴木一平, 大即信明, 西田孝弘, 河合慶有

    セメント技術大会講演要旨  2006.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • コンクリートの電気抵抗率がマクロセル腐食性状に与える影響

    日下部駿, NGUYEN THI THAO QUYNH, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会2021  2021.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • PAE系PCMの鉄筋腐食発生限界塩化物イオン濃度に関する実験的研究

    藤島幹大, 河合慶有, 大久保誠

    土木学会四国支部第30回技術研究発表会  2024.6 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • コンクリート中における酸素低減型混和材の腐食抑制効果に関する実験的検討

    石﨑名美, 河合慶有, 西田孝弘

    土木学会四国支部第30回技術研究発表会  2024.6 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • 機械学習を用いたコンクリートのひび割れ原因推定プログラムの提案

    近原大樹, 河合慶有, 西田孝弘

    土木学会四国支部第30回技術研究発表会  2024.6 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • 現場透気試験による構造体コンクリートの耐久性評価指標の検討

    國方翔太, 氏家勲, 河合慶有

    土木学会四国支部技術研究発表会  2014.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • 材料分離の影響を受けた水平鉄筋の腐食性状に及ぼす酸素透過の影響

    河合 慶有, 仲井 一平, 氏家 勲

    土木学会四国支部技術研究発表会  2017.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • 養生の相違がフライアッシュコンクリートの鉄筋腐食に及ぼす影響

    春日翔平, 三宅宏明, 氏家勲, 河合慶有

    土木学会四国支部技術研究発表会  2014.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • 透気試験方法の違いが養生条件の異なるコンクリートの透気係数と含水率の関係に及ぼす影響

    柴田真帆, 氏家勲, 河合慶有

    土木学会四国支部技術研究発表会  2014.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • 炭酸カルシウムに及ぼすバイオグラウトの配合要因に関する検討

    久保郁貴, 氏家勲, 河合慶有

    土木学会四国支部技術研究発表会  2014.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • コンクリートの初期養生及び材齢が電気泳動試験に及ぼす影響

    河合慶有, 氏家勲, 國方翔太

    土木学会年次学術講演会講演概要集(CD-ROM)  2014.8 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • 銅スラグ細骨材を使用したコンクリートに対する品質評価図の適用可能性

    久保勇登, 氏家勲, 河合慶有

    土木学会四国支部技術研究発表会  2016.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • 塩化物イオンの電気泳動特性に影響を及ぼす諸要因に関する検討

    門屋朱里, 吉田大貴, 氏家勲, 河合慶有

    土木学会四国支部技術研究発表会  2016.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • バイオ材料の炭酸カルシウム析出過程に及ぼす温度の影響

    山本沙也, Prima Yane Putri, 氏家勲, 河合慶有

    土木学会四国支部技術研究発表会  2016.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • フライアッシュの混和が配置高さの異なる水平鉄筋の腐食性状に与える影響

    仲井一平, 長野沙紀, 氏家勲, 河合慶有

    土木学会四国支部技術研究発表会  2016.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • 養生条件および材齢の相違が塩化物イオンの電気泳動特性に及ぼす影響

    高市茂, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会  2015.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • 骨材種類に起因する乾燥収縮量の違いがRC梁供試体の鉄筋腐食性状に及ぼす影響の検討

    仲井一平, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会  2015.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • コンクリート供試体の境界条件を考慮した透気係数‐含水率の関係に関する考察

    村上賢晃, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会  2015.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • 電気抵抗率測定を用いた鉄筋コンクリート内部劣化の定量化に関する基礎的研究

    岡田辰夫, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会  2015.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • フライアッシュ及び非鉄スラグ細骨材を用いたコンクリートの乾燥収縮ひび割れ抵抗性

    村上賢晃, 河合慶有, 氏家勲

    材料学会四国支部発表会  2016.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • コンクリートの材料分離が配置高さの異なる水平鉄筋の耐久性に及ぼす影響

    河合 慶有, 西村 沙希, 氏家 勲

    土木学会四国支部技術研究発表会  2015.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • 電気抵抗率測定を用いたコンクリート内部欠陥の検知手法の実験的検討

    喜多村征生, 岡田辰夫, 氏家勲, 河合慶有

    土木学会四国支部技術研究発表会  2016.5 

     More details

    Presentation type:Oral presentation (general)  

    researchmap

  • 微生物を利用したコンクリートの補修技術 Invited

    河合 慶有

    関西道路研究会  2018.7 

     More details

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    researchmap

  • 好気性微生物による貧酸素環境がセメント硬化体中の酸素透過に与える影響

    杉谷紗理, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会  2019.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • 枯草菌の微生物代謝を利用した断面修復材の基礎的研究

    阿部光一郎, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会  2019.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • 自己治癒カプセルを用いたモルタルの乾燥収縮ひび割れ抵抗性

    坂井大河, 河合慶有, 氏家勲

    土木学会四国支部技術研究発表会2020  2020.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

  • コンクリート中の溶存酸素に着目した腐食抑制方法について Invited

    河合 慶有

    マルチフィールド研究会  2016.10 

     More details

    Language:Japanese   Presentation type:Oral presentation (invited, special)  

    researchmap

  • 銅スラグ細骨材を用いたコンクリートの高性能化について Invited

    河合 慶有

    JCI四国支部研究委員会 講習会  2016.6 

     More details

    Language:Japanese   Presentation type:Public lecture, seminar, tutorial, course, or other speech  

    researchmap

  • 枯草菌の代謝を用いたカプセル中の炭酸カルシウム析出過程の検討

    奥野 宙, 河合 慶有, 氏家 勲

    土木学会四国支部技術研究発表会  2017.5 

     More details

    Language:Japanese   Presentation type:Oral presentation (general)  

    researchmap

▼display all

Industrial property rights

  • 混和材料,セメントの練混ぜ方法,セメント系プレミックス材料,鉄筋コンクリートの腐食防止方法

    河合 慶有

     More details

    Application no:特願2016-087837  Date applied:2016.4

    Announcement no:特開2017-197393  Date announced:2017.11

    Patent/Registration no:特許第6716331号  Date registered:2020.6 

    researchmap

  • 補修材料及び補修方法

    河合慶有

     More details

    Application no:特願2017-071416 

    Patent/Registration no:特許第6871570号 

    researchmap

Awards

  • 学長賞

    2021   愛媛大学  

    河合慶有

     More details

  • 学長特別賞

    2020   愛媛大学  

    河合慶有

     More details

  • 論文奨励賞

    2018.3   日本材料学会   初期養生がフライアッシュコンクリート中の 腐食因子の侵入と鉄筋腐食抵抗性に与える影響

    河合 慶有, 氏家 勲

     More details

  • SCI excellence award

    2013.11   Singapore Concrete Institute  

    河合 慶有

     More details

  • SINGA award

    2009.8   Agency for Science, Technology and Research  

    河合 慶有

     More details

  • 修士論文発表会ベストプレゼンテーション賞

    2006.2   東京工業大学  

    河合慶有

     More details

▼display all

Research Projects

  • 教育用デジタルプラットフォームの構築と技術者教育・アウトリーチ活動への展開

    2023.11 - 2028.3

    内閣府  戦略的イノベーション創造プログラム(SIP)スマートインフラマネジメントシステムの構築 

      More details

    Authorship:Coinvestigator(s) 

    researchmap

  • 電気化学・光学計測に基づく鉄筋腐食機構の再整理と物理化学連成解析による検証

    2023.4 - 2026.3

    日本学術振興会 科学研究費助成事業 基盤研究(B)  基盤研究(B)

    河合 慶有

      More details

    Authorship:Principal investigator 

    researchmap

  • Norway-Japan-China Consortium on Smart and Sustainable Road and Rail Infrastructure (ConStruct)

    2023.1 - 2026.12

    Norwegian Agency for International Cooperation and Quality Enhancement in Higher Education  UTFORSK UTF-2021/10090  Construction engineering, architecture (403)

    PI: Assoc. Prof. Jian Dai, Co-PI: Assoc. Prof. Keiyu Kawaai

      More details

    Authorship:Principal investigator 

    researchmap

  • Development of concrete with corrosion inhibition of steel bar and antibacterial using copper slag

    2022.4 - 2025.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

      More details

    Grant amount:\4290000 ( Direct Cost: \3300000 、 Indirect Cost:\990000 )

    researchmap

  • Corrosion factors of underground steel considering reaction/transportation of substances and proposal of countermeasure for the corrosion protection

    2020.4 - 2023.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research  Grant-in-Aid for Scientific Research (C)

      More details

    Grant amount:\4420000 ( Direct Cost: \3400000 、 Indirect Cost:\1020000 )

    researchmap

  • 微生物代謝を利用した高機能コンクリートの開発

    2019.11 - 2021.3

    JST  A-STEP機能検証フェーズ 

    河合 慶有

      More details

    Authorship:Principal investigator  Grant type:Competitive

    researchmap

  • Evaluation techniques on corrosion resistance based on oxygen permeability

    2019.4 - 2023.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)  Grant-in-Aid for Scientific Research (B)

      More details

    Grant amount:\17030000 ( Direct Cost: \13100000 、 Indirect Cost:\3930000 )

    researchmap

  • Effect of self-healing in concrete and an assessment technique based on corrosion resistance

    2017.4 - 2020.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (A)  Grant-in-Aid for Young Scientists (A)

    Kawaai Keiyu

      More details

    Grant amount:\14430000 ( Direct Cost: \11100000 、 Indirect Cost:\3330000 )

    This study reports on the enhancement of corrosion resistance owing to reduction of dissolved oxygen associated with microbial activity in pores formed in hardened concrete. When mixed in concrete, corrosion current density with respect to microcell and macrocell corrosion is clearly decreased after exposed to wet and dry cycles using tap water containing NaCl 3%. This could be explained by the fact that oxygen permeability is decreased owing to reduced availability of dissolved oxygen determined by cathodic polarization properties. This led to lowered half-cell potentials which indicates the possibility of reduced oxygen concentrations in pore solution in hardened concrete. In addition, the beneficial effect on the corrosion resistance is clearer in the case of specimens tested under saturated conditions.

    researchmap

  • Study on practical application of repair method of concrete crack using microbial metabolism

    2015.4 - 2019.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B)  Grant-in-Aid for Scientific Research (B)

    Ujike Isao

      More details

    Grant amount:\17810000 ( Direct Cost: \13700000 、 Indirect Cost:\4110000 )

    The filler made of calcium carbonate precipitated by the reaction of carbon dioxide with a calcium source due to the metabolism of microorganisms is called bio-grout. For practical application of repair method by bio-grout, the purpose of this research is to find out the conditions of high precipitation rate of calcium carbonate and to study the method of filling in the places where cracks and water leaks.
    Although the precipitation rate of calcium carbonate changes depending on the composition of bio-grout and its concentration and temperature, It became clear that that calcium carbonate can maintain a high precipitation rate when the pH of bio-grout does not fall below 7.5 after 24 hours by properly adjusting the alkaline buffer action. Moreover, water leakage can be stopped by injecting bio-grout repeatedly into a crack.

    researchmap

  • Estimation method for durability performance in cover concrete adversely affected by segregation

    2015.4 - 2017.3

    Japan Society for the Promotion of Science  Grants-in-Aid for Scientific Research Grant-in-Aid for Young Scientists (B)  Grant-in-Aid for Young Scientists (B)

    Kawaai Keiyu

      More details

    Authorship:Principal investigator  Grant type:Competitive

    Grant amount:\4290000 ( Direct Cost: \3300000 、 Indirect Cost:\990000 )

    This study examined the effect of heterogeneity of cover concrete caused by segregation on the resistance against ingress of substances. Air permeability coefficients tended to increase in upper parts of column specimens cast with OPC mixture with typical bleeding water. Based on the results of air permeability and moisture content obtained up to the age of 180 days of monitoring, this study showed that the durability estimation technique based on the relationship between two variables can be applied to assess the heterogeneity such as porous structures formed owing to bleeding water in a form of segregation in column specimen. On the other hand, the ingress of chloride ions tended to increase in those regions affected by bleeding water, which partly contribute to higher microcell corrosion current density. It should be noted that total corrosion current density was likely to increase with higher rate of oxygen permeability measured via cathodic polarization in this study.

    researchmap

▼display all

Teaching Experience (On-campus)

▼display all

Teaching Experience

  • 科学技術英語

    2023.4

     More details

  • 研究倫理特論

    2023.4

     More details

  • 実践アセットマネジメント

    2023.4

     More details

  • 瀬戸内工学

    2020.4

     More details

  • 工学入門

    2020.4 - 2020.9 Institution:愛媛大学

     More details

  • 物理学入門

    2019.4 - 2023.3 Institution:愛媛大学

     More details

  • 技術英語プレゼンテーション

    2019.4 - 2022.3

     More details

  • 社会資本の整備と運用

    2014.4 Institution:愛媛大学

     More details

  • 建設材料学

    2014.4 Institution:愛媛大学

     More details

  • コンクリート実験

    2014.4 - 2023.3 Institution:愛媛大学

     More details

  • 測量学実習

    2014.4 - 2022.3 Institution:愛媛大学

     More details

  • 構造力学Ⅰ同演習

    2014.4 - 2018.3 Institution:愛媛大学

     More details

  • Computer Applications in Civil Engineering

     More details

  • Structural Mechanics and Materials

     More details

▼display all

Social Activities

  • 愛媛県生コンクリート品質監査会議

    Role(s): Organizing member

     More details

  • ME養成講座

    Role(s): Lecturer

    愛媛大学防災情報研究センター 

     More details

    Type:Visiting lecture

    researchmap

Media Coverage

  • デジタル活用で点検効率化/人材育成ツール開発へ Newspaper, magazine

    建設工業新聞  2024.3

     More details

  • 納豆菌で鉄筋を防錆 Newspaper, magazine

    コンクリート新聞(週刊)第2718号  2023.11

     More details

    Author:Other 

    researchmap

  • 納豆菌でコンクリートが長持ち 自己治癒に加え鉄筋腐食を抑制 Newspaper, magazine

    日経コンストラクション  2021.7

     More details

  • 菌の呼吸、建物補修に全集中 自分で直す材料を開発 Newspaper, magazine

    日本経済新聞  科学&新技術  2021.3

     More details