Flexural Toughness of Basalt Fibre-Reinforced Shotcrete and Industrial-Scale Testing
Flexural Toughness of Basalt Fibre-Reinforced Shotcrete and Industrial-Scale Testing
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DOI：
10.1155/2019/6568057
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发表时间：
2019-10-31
影响因子：
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通讯作者：
Yang, Yixuan
中科院分区：
文献类型：
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作者：
Jiao, Huazhe;Wu, Yachuang;Yang, Yixuan
研究了玄武岩纤维喷射混凝土的增韧问题。结合巷道支护变形监测试验，进行了井下射养梁四点弯曲试验。根据韧性标准，即DBV-1998，JSCE SF-4和核磁共振（NMR）孔隙测试，分析了弯曲性能。结果表明，当玄武岩纤维（BF）掺量为0 ~ 7.5kg/m3时，在相同的变形量下，18 mm的BF可以显著提高残余应力，而不是提高抗弯强度的峰值。同时，弯曲韧性的趋势在3- 4.5kg/m3的剂量下增加到峰值，然后是下降曲线。根据尺寸，NMR测试的孔可以分为三种类型：（1）封闭孔，R < 0.01 μ m，（2）毛细孔，0.01 μ m < R < 5 μ m，和（3）连通孔，R > 5 μ m。连通孔隙是有害的，对喷射混凝土性能起着至关重要的作用。此外，巷道壁的变形显着抑制BFRS，80天收敛约为2毫米，这是只有25%的控制。最后，综合结果表明，3-4.5 kg/m3的剂量范围可以对BFRS性能表现出合理的有益效果。
This study focuses on toughness enhancement of basalt fibre-reinforced shotcrete (BFRS). Four-point bending experiments of underground shooting and curing beams combined with a roadway-supporting deformation monitoring test were conducted. The flexural performance was analysed based on the toughness standards, namely, DBV-1998, JSCE SF-4, and nuclear magnetic resonance (NMR) pore testing. The results demonstrate that, given a basalt fibre (BF) dosage of 0-7.5 kg/m(3), 18 mm BF can significantly increase the residual stress under the same deformation, rather than the peak values of the flexural strength. Meanwhile, the trend in the flexural toughness increases to a peak at a dosage of 3-4.5 kg/m(3), followed by a declining curve. The pores from an NMR test can be divided into three types based on size: (1) closed pores, R < 0.01 mu m, (2) capillary pores, 0.01 mu m < R < 5 mu m, and (3) connected pores, R > 5 mu m. The connected pores are detrimental, playing a crucial role in the shotcrete performance. Furthermore, the deformations of the roadway walls are significantly restrained by the BFRS, and the 80-day convergences are approximately 2 mm, which is only 25% of the control. Finally, the comprehensive results indicate that a dosage range of 3-4.5 kg/m(3) can demonstrate reasonable beneficial effects for the BFRS performance.