In order to strengthen the stability of cement paste backfill ( CPB) , fibers were included into paste filling material ( CPFM) to improve its brittleness. The failure behavior of the polypropylene fiber reinforced CPFM was studied by means of macro-meso experimental investigations. At the macro-scale, the influence of polypropylene fiber content on the mechanical properties of CPFM was studied quantitatively by a series of uniaxial compression tests. The influence of fiber on the meso-structure of cement paste backfill specimens was analyzed by the X-ray computed tomography multi-slice scanning technique . The results show that the addition of fibers increases the peak strength of the CPFM slightly at the cement content of 10℅. It improved toughness and the strain at peak strength significantly. CT results show that fibers can make cracks finer and more uniform by preventing their expansion and extension, then a larger volume of cracks absorbing more energy exists in specimen before the damage, thus it improves the toughness of CPFM.%为了提高膏体充填体的稳定性,在膏体充填材料中加入纤维以改善其脆性. 采用宏细观试验方法研究了聚丙烯纤维增强膏体充填材料的破坏行为. 从宏观上,通过一系列单轴压缩试验定量研究了纤维掺量对膏体充填材料力学性能影响. 采用X射线CT多层切片扫描技术分析了纤维对膏体充填体试件细观结构的影响. 研究结果表明:水泥掺量为10℅时,纤维使膏体充填材料的峰值强度略有增加,纤维可大幅度提高其韧度和峰值强度点的应变;纤维能阻止试件中裂缝的扩展和延伸,使裂缝细化、分散,进而使试件在破坏前可形成更大体积的裂缝,这些裂缝在形成过程中可吸收更多的能量,从而提高膏体充填材料的韧性.
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