Cracking mechanism and structural performances of concrete damaged by delayed ettringite formation

• Project/Area Number: 18K04299
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 22010:Civil engineering material, execution and construction management-related
• Research Institution: Hokkaido University (2019-2020); The University of Tokyo (2018)
• Principal Investigator: Matsumoto Koji 北海道大学, 工学研究院, 准教授 (10573660)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2020: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000); Fiscal Year 2019: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000); Fiscal Year 2018: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
• Keywords: コンクリート / 遅延エトリンガイト生成 / 膨張ひずみ / 構造性能 / 発生メカニズム / 構造実験 / 数値解析

Outline of Final Research Achievements

Cracking mechanism of concrete damaged by delayed ettringite formation and its influence on the structural performance were investigated. Meso-scale discrete analyses considering volume changes revealed that expanded regions significantly affect cracking patterns caused by paste expansion. Contribution of interface expansive pressure and paste expansion was also investigated from ring type expansion tests using an artificial aggregate. As for the structural performances, the effect of delayed ettringite formation on flexural capacities and shear capacities of PC sleepers of Indian Railways were experimentally investigated as case examples. Furthermore, the calculation method for flexural capacity was considered.

Academic Significance and Societal Importance of the Research Achievements

インフラの老朽化に伴い，わが国のみならず，維持管理の合理化は世界的な課題である．遅延エトリンガイト生成は，比較的最近になって認知されてきたコンクリートの損傷形態であり，その発生メカニズムはいまだ不明な点が多い．本研究は，遅延エトリンガイト生成により発生するコンクリートのひび割れを力学的視点に基づいて検討したもので，世界的にも先駆的な結果を得ている．また，維持管理で重要となる構造性能に着目し，遅延エトリンガイト生成が曲げおよびせん断耐力に及ぼす影響を明らかにした．本研究成果は，世界中に膨大にあるコンクリート構造物に対する維持管理の合理化に資するものであり，大きな社会的意義を持っている．

Research Products

• [Journal Article] “Expansive Cracking and Compressive Failure Simulations of ASR and DEF Damaged Concrete Using a Mesoscale Discrete Model (2019)
  • Author(s): Yi Wang, Yushi Meng, Punyawut Jiradilok, Koji Matsumoto, Kohei Nagai and Shingo Asamoto
  • Journal Title: Cement and Concrete Composites Volume: Vol. 104
  • Peer Reviewed
• [Journal Article] Visual Investigation Method and Structural Performance Evaluation for DEF Induced Damaged Indian Railway PC Sleepers (2018)
  • Author(s): Rajamurugan Sundaram, Koji Matsumoto, Kohei Nagai and Anupam Awasthi
  • Journal Title: Journal of Asian Concrete Federation Volume: Vol. 4, No. 2 Pages: 103-115
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] Cause Estimation and Proposal of Inspection Method for PC Sleepers of Indian Railways (2018)
  • Author(s): Koji Matsumoto, Kohei Nagai, Rajamurugan Sundaram and Anupam Awasthi
  • Organizer: 17th International Symposium on New Technologies for Urban Safety of Mega Cities in Asia
  • Int'l Joint Research
• [Presentation] インド鉄道・損傷 PC マクラギの構造性能評価と外観目視点検手法 (2018)
  • Author(s): 松本浩嗣，Rajamurugan Sundaram，長井宏平，Anupam Awasthi
  • Organizer: 既設コンクリートの構造性能評価に関するシンポジウム