| 摘要: |
| 为研究超高韧性水泥基复合材料（UHTCC）在超低温环境下的断裂性能，设计了5组不同纤维掺量的UHTCC预制裂缝切口梁，在经过超低温作用后进行三点弯曲加载试验，通过分析计算UHTCC的荷载-挠度曲线，评价了超低温环境下UHTCC的断裂性能.结果表明：当纤维掺量为1.5%时，UHTCC性能的提升效果最优，当纤维掺量超过1.5%时，UHTCC的性能略有降低；超低温作用后UHTCC的强度显著提升，当处理温度由常温降至-160 ℃时，材料表现出明显的脆性，其延性指数、特征长度及失稳断裂韧度均明显降低. |
| 关键词: 超高韧性水泥基复合材料 超低温 断裂韧度 断裂能 延性指数 |
| DOI：10.3969/j.issn.1007-9629.2022.09.003 |
| 分类号:TB332 |
| 基金项目:湖北省自然科学基金资助项目（2020CFB860） |
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| Effect of Ultra-low Temperature on Fracture Behavior of Ultra-high Toughness Cementitious Composites |
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QIAN Weimin1, SU Jun1,2, ZHAO Jiayu1, JI Wei1
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1.School of Civil Engineering and Environment， Hubei University of Technology， Wuhan 430068， China;2.Engineering and Technology College， Hubei University of Technology， Wuhan 430068， China
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| Abstract: |
| In order to further study the fracture property of ultra-high toughness cementitious composite（UHTCC） under ultra-low temperature environment， five groups of UHTCC prefabricated crack notched beams with different fiber contents were designed. After ultra-low temperature and cryogenic treatment， three-point bending loading test was carried out. The fracture performance of UHTCC under ultra-low temperature environment was evaluated by analyzing and calculating the load-deflection curve of UHTCC. The results show that the performance improvement effect of UHTCC with the fiber content of 1.5% is the best. After the fiber content exceeding 1.5%， the performance of UHTCC is slightly reduced. The strength of UHTCC increases significantly after ultra-low temperature. When the temperature reaches -160 °C， the material shows obvious brittleness， and its ductility index， characteristic length and unstable fracture toughness are significantly reduced. |
| Key words: ultra-high toughness cementitious composite ultra-low temperature fracture toughness fracture energy ductility index |
