Enhancement in self-compactability of fresh concrete by finer entrained air bubbles

• Project/Area Number: 16K06445
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Civil engineering materials/Construction/Construction management
• Research Institution: Kochi University of Technology
• Principal Investigator: Ouchi Masahiro 高知工科大学, システム工学群, 教授 (80301125)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Project Status: Completed (Fiscal Year 2018)
• Budget Amount: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2017: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000); Fiscal Year 2016: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
• Keywords: 自己充填コンクリート / 連行気泡 / 微細気泡 / 自己充填性 / フレッシュコンクリート / 粘着力 / 増粘剤 / ベアリング効果 / 連行空気泡 / 新型増粘剤 / 微細空気泡 / フライアッシュ / 固体粒子間摩擦低減 / 空気泡 / 消泡剤 / 気泡浮上 / 空気量経時変化 / ボールベアリング効果 / 土木材料 / コスト縮減

Outline of Final Research Achievements

An effective method for entraining fine air bubbles into fresh self-compacting concrete was established by lowering the viscosity of mortar phase. The size-effect of entrained air bubbles on mitigation in friction between solid particles of fresh self-compacting concrete during deformation and the floating by comparing with fly ash. Higher adhesion force attached to fresh mortar enhanced resistance to segregation of fresh concrete attained by a new type of viscosity agent and it assured self-compactability of fresh concrete with lower unit cement content. The viscosity agent also enhanced in keeping air content of fresh concrete and lowered the averaged diameter of entrained air bubbles.

Academic Significance and Societal Importance of the Research Achievements

鉄筋を有する型枠内に重力の作用だけで充填し，振動締固め作業が不要である，施工の省力化および耐久性の向上に有効な自己充填コンクリートの普及・一般化を促進するための技術を開発した。高強度を必要としない一般の構造物用に，セメント量を減らして骨材量を増加させつつも自己充填性を維持することが可能な，経済性向上に有効である。高強度を必要としない場合でも，従来の自己充填コンクリートは普通コンクリートの約2倍の材料単価であったものから，微細気泡の連行とモルタル相への粘着力の付与により，約4割のコスト縮減を可能にする技術である。

Research Products

• [Journal Article] Effects of fly ash, mixing procedure and type of air-entraining agent on coalescence of entrained air bubbles in mortar of self-compacting concrete at fresh state (2018)
  • Author(s): Puthipad Nipat、Ouchi Masahiro、Attachaiyawuth Anuwat
  • Journal Title: Construction and Building Materials Volume: 180 Pages: 437-444
  • DOI: 10.1016/j.conbuildmat.2018.04.138
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Critical Size of Entrained Air to Stability of Air Volume in Mortar of Self-Compacting Concrete at Fresh Stage (2017)
  • Author(s): Sovannsathya Rath, Nipat Puthipad, Anuwat Attachaiyawuth, Masahiro Ouchi
  • Journal Title: Journal of Advanced Concrete Technology Volume: 15 Issue: 1 Pages: 29-37
  • DOI: 10.3151/jact.15.29
  • NAID: 130005310927
  • ISSN: 1346-8014, 1347-3913
  • Year and Date: 2017-01-27
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Improvement in Self-compacting Properties of Fresh Concrete by Eliminating Large Air Bubbles using an Antifoaming Agent (2017)
  • Author(s): Masahiro Ouchi, Kenta Kameshima, Anuwat Attachaiyawuth
  • Journal Title: Journal of Advanced Concrete Technology Volume: 15 Issue: 1 Pages: 10-18
  • DOI: 10.3151/jact.15.10
  • NAID: 130005310946
  • ISSN: 1346-8014, 1347-3913
  • Year and Date: 2017-01-27
  • Peer Reviewed / Open Access / Acknowledgement Compliant
• [Journal Article] Enhanced entrainment of fine air bubbles in self-compacting concrete with high volume of fly ash using defoaming agent for improved entrained air stability and higher aggregate content (2017)
  • Author(s): Puthipad Nipat、Ouchi Masahiro、Rath Sovannsathya、Attachaiyawuth Anuwat
  • Journal Title: Construction and Building Materials Volume: 144 Pages: 1-12
  • DOI: 10.1016/j.conbuildmat.2017.03.049
  • Peer Reviewed
• [Journal Article] Improving the stability of entrained air in self-compacting concrete by optimizing the mix viscosity and air entraining agent dosage (2017)
  • Author(s): Rath Sovannsathya、Ouchi Masahiro、Puthipad Nipat、Attachaiyawuth Anuwat
  • Journal Title: Construction and Building Materials Volume: 148 Pages: 531-537
  • DOI: 10.1016/j.conbuildmat.2017.05.105
  • Peer Reviewed
• [Journal Article] Enhancement in self-compactability and stability in volume of entrained air in self-compacting concrete with high volume fly ash (2016)
  • Author(s): Nipat Puthipad, Masahiro Ouchi, Sovannsathya Rath, Anuwat Attachaiyawuth
  • Journal Title: Construction and Building Materials Volume: 128 Pages: 349-360
  • Peer Reviewed / Acknowledgement Compliant
• [Presentation] 粗骨材・モルタル間の粘着力向上によるフレッシュコンクリートへの自己充填性付与 (2018)
  • Author(s): 大西悠，大内雅博，田中嘉雄，小西秀和
  • Organizer: 土木学会第73回年次学術講演会
• [Presentation] 空気を連行したフレッシュ時の自己充てんコンクリート中の固体粒子間摩擦に及ぼす細骨材の物理的特性の影響 (2017)
  • Author(s): 中村巴大
  • Organizer: 平成29年度土木学会年次学術講演会