| 摘要: |
| 对3类不同粉煤灰掺量下形成的聚乙烯醇(PVA)纤维水泥基材料，通过三点弯曲试验测试，研究了PVA纤维水泥基材料的弯曲性能；通过对PVA纤维水泥基材料断裂面处纤维表面、纤维嵌入端和纤维拉断或拔出端的扫描电镜影像分析，研究了PVA纤维(水泥)基体界面微观结构，揭示了PVA纤维桥接裂缝过程；通过PVA纤维水泥基材料样本抛光表面的荧光影像，量化测定了PVA纤维在基体中的分布.结果表明：掺入粉煤灰后PVA纤维对水泥基材料增强增韧作用增加，高掺量下效果更显著；掺入粉煤灰后裂缝处PVA纤维的桥接应力和纤维基体界面黏结力降低，随着裂缝的扩展，PVA纤维由短距离滑动转变为长距离滑动，纤维桥接裂缝的效率提高，增强增韧的作用增加；掺入粉煤灰后基体结构更加均匀，PVA纤维分布系数增大，PVA纤维对水泥基材料的增强增韧作用提高. |
| 关键词: 聚乙烯醇纤维 纤维桥接裂缝 纤维分布 纤维增强增韧 水泥基材料 界面微观结构 |
| DOI：103969/j.issn1007 9629201602024 |
| 分类号: |
| 基金项目:国家自然科学基金资助项目(11362013)；教育部高等学校博士学科点专项科研基金(优先发展领域)项目(20121514130001)；内蒙古自治区高等学校科学研究项目(NJZY330) |
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| Effects of the Process of Polyvinyl Alcohol(PVA) Fiber Bridging Cracks andFiber Distribution on the Bending Properties of Cementitious Composites |
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NIU Hengmao1, WU Wenhong2, XING Yongming3, ZHAO Yanru4
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1.College of Construction Engineering, Inner Mongolia Technical College of Construction, Hohhot 010070, China;2.College of Information Engineering, Inner Mongolia University of Technology, Hohhot 010051, China;3.College of Science, Inner Mongolia University of Technology, Hohhot 010051, China;4.College of Civil Engineering, Inner Mongolia University of Technology, Hohhot 010051, China
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| Abstract: |
| Three fly ash(FA) contents were selected to form three types of polyvinyl alcohol(PVA) fiber reinforced cementitious composites(PFRCCs). Three point bending test was implemented to evaluate the bending properties of PFRCC; SEM micrographs of PVA fiber surface, embedded and ruptured or pullout end of fiber in fracture surface were used to investigate PVA fiber matrix interface microstructure so as to reveal the process of PVA fiber bridging cracks; PVA fibers distribution was quantitatively measured by the fluorescence images on polishing surface of PFRCC sample. The test results show that the degree of PVA fibers reinforcing and toughening increases when adding FA. Moreover, the degree is remarkably improved when adding high content of FA; PVA fibers bridging stress in cracks and PVA fiber matrix interface bonding ability decrease with adding FA. Along with the expansion of cracks, PVA fibers bridging cracks changes from short slippage to long slippage, with the result that the efficiency of PVA fibers bridging cracks is significantly improved and the effect of fiber reinforcing and toughening is increased. The uniform cementious matrix formation due to FA addition leads to good fiber distribution, which promotes bending strength and toughness of PFRCC. |
| Key words: polyvinyl alcohol(PVA) fiber fiber bridging crack fiber distribution fiber reinforcing and toughening cementitious composite interface microstructure |
