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纤维自密实混凝土的压拉性能及混杂效应

Compressive-tensile Properties and Hybrid Effect of Fiber Self-compacting Concrete

  • 摘要: 在自密实混凝土(SCC)中单掺、混掺玄武岩纤维(BF)和聚丙烯腈纤维(PAN)制备纤维SCC试件,对标准养护28 d的纤维SCC试件进行强度试验,研究单掺、混掺BF与PAN含量对SCC压拉性能的影响,探讨纤维SCC的微观结构和纤维的混杂效应。结果表明:掺入BF和PAN均能提升SCC的压拉强度,且劈裂抗拉强度的提升效果较抗压强度明显;单掺纤维对SCC抗压强度的提升效果较混掺纤维显著,混掺纤维对SCC劈裂抗拉强度的提升效果优于单掺纤维,混掺BF体积分数为0.10%、PAN体积分数为0.12%时,纤维SCC劈裂抗拉强度提升效果最显著,较SCC提高了75.45%;SCC内部裂缝较明显,掺入的纤维在SCC内部生成网状结构,对于抗压强度呈负混杂效应,对于劈裂抗拉强度呈正混杂效应。

     

    Abstract: Fiber self-compacting concrete (SCC) specimens were prepared by mixing basalt fiber (BF) and polyacrylonitrile fiber (PAN) with different contents in SCC. The strength test of fiber SCC specimens after standard curing for 28 d was carried out to study the influence of the content of BF and PAN on the compressive and tensile properties of SCC, and explore the microstructure of fiber SCC and the hybrid effect of fibers. The results show that the incorporation of BF and PAN can improve the compressive strength of SCC, and the improvement effect of splitting tensile strength is more obvious than that of compressive strength. The improvement effect of single fiber on the compressive strength of SCC is more obvious than that of mixed fiber, and the improvement effect of mixed fiber on the splitting tensile strength of SCC is better than that of single fiber. When the volume fraction of BF and PAN is 0.10% and 0.12% respectively, the improvement effect of fiber on the splitting tensile strength of SCC is the most obvious, which is 75.45% higher than that of SCC. The internal cracks of SCC are obvious, and the mixed fiber forms a network structure in SCC, which has a negative hybrid effect on compressive strength and a positive effect on splitting tensile strength.

     

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