纤维混凝土抗弯与抗压增强的分异特性试验研究

Experimental Research on Differentiation Characteristics of Concrete Flexural and Compressive Enhancement of Fiber

  • 摘要: 纤维混凝土越来越多地成为巷道支护中喷射混凝土的首选材料。为分析常用纤维对混凝土的增强效果及增强机理,以便于不同工程纤维混凝土选取合理的纤维类型和掺量,选取了钢纤维、玻璃纤维、聚丙烯纤维作为研究对象,通过混凝土力学试验研究了不同掺量的该三种纤维对混凝土抗弯强度和抗压强度的增强规律。结果表明:钢纤维、玻璃纤维和聚丙烯纤维混凝土抗弯强度最大增幅对应的纤维掺量分别为2.0%、1.5%、2.0%,其中抗弯强度增幅最大的为聚丙烯纤维,3 d和28 d的最大增幅分别为192%和138.6%;钢纤维、玻璃纤维和聚丙烯纤维混凝土抗压强度最大增幅对应的纤维掺量分别为0.5%、1.0%、2.0%,其中抗压强度增幅最大的为聚丙烯纤维,3 d和28 d的最大增幅分别为20.25%和18.3%;三种类型纤维对混凝土抗弯强度的最大增强效果排序为聚丙烯纤维>钢纤维>玻璃纤维,对混凝土抗压强度的最大增强效果排序为聚丙烯纤维>玻璃纤维>钢纤维;三种类型纤维对混凝土抗压强度的增强效果远低于对混凝土抗弯强度的增强效果。纤维混凝土的增强特性试验结果可为矿山巷道支护提供参考。

     

    Abstract: Fibrous concrete is increasingly being used as the preferred material for shotcrete in roadway support. In order to analyze the enhancement effect and mechanism of commonly used fibers on concrete, and to select reasonable fiber types and dosages for fiber-reinforced concretes in different engineerings, steel fiber, glass fiber, and polypropylene fiber are selected as research objects. The enhancement laws of these three types of fibers with different dosages on the concrete flexural strength and compressive strength are studied through concrete mechanics testings. The results show that the fiber dosages corresponding to the maximum increases in concrete flexural strength of steel fiber, glass fiber, and polypropylene fiber is 2.0%, 1.5%, and 2.0%, respectively. Among them, polypropylene fiber has the largest increase in flexural strength, with a maximum increase of 192% and 138.6% at 3 days and 28 days, respectively; The fiber dosages corresponding to the maximum increases in concrete compressive strength of steel fiber, glass fiber, and polypropylene fiber is 0.5%, 1.0%, and 2.0%, respectively. Among them, polypropylene fiber has the largest increase in compressive strength, with a maximum increase of 20.25% and 18.3% at 3 days and 28 days, respectively; The maximum enhancement effect of the three types of fibers on the concrete flexural strength is ranked as polypropylene fiber>steel fiber>glass fiber, and the maximum enhancement effect of the three types of fibers on the concrete compressive strength is ranked as polypropylene fiber>glass fiber>steel fiber; The enhancement effect of the three types of fibers on the concrete compressive strength is much lower than that on the concrete flexural strength. The test results on the reinforcement characteristics of fiber-reinforced concrete can serve as a reference for mine roadway support.

     

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