| 摘要: |
| 通过18组共90根纳米SiO2和聚乙烯醇（PVA）纤维增强水泥基复合材料预制切口小梁试件的三点弯曲断裂试验，以起裂断裂韧度和断裂能作为评价指标，探讨了纳米SiO2掺量、PVA纤维体积分数及石英砂粒径对水泥基复合材料断裂性能的影响.结果表明：适量的纳米SiO2和PVA纤维可显著改善试件的断裂性能，在未掺纳米SiO2或纳米SiO2掺量为2.0%条件下，随着PVA纤维体积分数的增加，试件的起裂断裂韧度和断裂能均呈现先增后减趋势，且均在PVA纤维体积分数为1.2%时达到最大值.当纳米SiO2掺量小于1.5%时，试件的断裂性能随着纳米SiO2掺量的增加而提高；当纳米SiO2掺量大于1.5%时，纳米SiO2的掺入对试件的断裂性能有不利影响；随着石英砂粒径的减小，试件的断裂性能逐渐降低. |
| 关键词: 水泥基复合材料 PVA纤维 纳米SiO2 起裂断裂韧度 断裂能 |
| DOI：10.3969/j.issn.1007-9629.2021.05.002 |
| 分类号:TU528.0 |
| 基金项目:国家自然科学基金资助项目（51678534）；河南省高校科技创新团队支持计划（20IRTSTHN009） |
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| Fracture Properties of Nano-SiO2 and PVA Fiber Reinforced Cementitious Composites |
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ZHANG Peng, KANG Luoyi, GUO Jinjun, WANG Juan
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School of Water Conservancy Engineering， Zhengzhou University， Zhengzhou 450001， China
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| Abstract: |
| Through three-point bending fracture test of 18 groups of 90 pre-cut beam specimens of cementitious composite， the effect of polyvinyl alcohol （PVA） fiber and nano-SiO2 contents on fracture properties of cementitious composite was revealed on condition that PVA fiber and nano-SiO2 was added alone and by blending. The initial fracture toughness and fracture energy were used to evaluate fracture properties of cementitious composite. The results show that a moderate amount of PVA fiber and nano-SiO2 incorporation can improve fracture properties of cementitious composite significantly. The initial fracture toughness and fracture energy of the beam specimens of cementitious composite without nano-SiO2 and cementitious composite containing 2.0% nano-SiO2 increase first and then decrease with the increase of PVA fiber volume content， and all the fracture parameters reach the maximum in the volume fraction of 1.2% of PVA fiber. When the content of nano-SiO2 is less than 1.5%， the fracture properties of PVA fiber reinforced cementitious composite improve gradually with the increase of nano-SiO2 content， however， the fracture properties of PVA fiber reinforced cementitious composite are adversely affected when the content of nano-SiO2 exceeds 1.5%. With the decrease of quartz sand particle size， the fracture properties of nano-SiO2 and PVA fiber reinforced cementitious composite decrease gradually. |
| Key words: cementitious composite PVA fiber nano-SiO2 initial fracture toughness fracture energy |
