Chen Xin, Shi Xiuzhi, Zhang Shu, Chen Hui, Zhou Jian, Yu Zhi, Huang Peisheng
School of Resources and Safety Engineering, Central South University, Changsha, Hunan 410083, China.
Fankou Lead-Zinc Mine, Shaoguan, Guangdong 512325, China.
Materials (Basel). 2020 Feb 5;13(3):718. doi: 10.3390/ma13030718.
This experimental investigation was conducted to research the properties of polypropylene (PP) fiber-reinforced cemented paste backfill (CPB). The unconfined compressive strength (UCS) of the fiber-reinforced CPB showed a significant improvement with average UCS increase ratios of 141.07%, 57.62% and 63.17% at 3, 7 and 28 days, respectively. The macroscopic failure mode and SEM analysis indicated that fibers prevented the formation of large tensile and shear cracks during the pull-out and pull-off failure modes. A linear fitting function for the UCS at a curing time of 3 days and two polynomial fitting functions for the UCS at curing times of 7 and 28 days were established to characterize the relationship between the UCS of the fiber-reinforced and unreinforced CPB. Moreover, based on composite mechanics, nonlinear models related to the UCS and fiber reinforcement index were obtained. The estimated functions containing the fiber reinforcement index , which consists of the fiber content and aspect ratio of fiber, could evaluate the UCS. Furthermore, the fiber reinforcement index quantifies the enhancement by the fibers. Both estimation results indicated that the UCS values were estimated accurately at curing times of 3, 7 and 28 days in this study. Additionally, the estimation models could be used to guide the strength design of fiber-reinforced CPB. Besides this, the results showed that fiber-reinforced CPB can be used more widely in mine backfills and meets the requirements of controlled low-strength material (CLSM) for broader applications.
本实验研究旨在探究聚丙烯（PP）纤维增强胶结充填料（CPB）的性能。纤维增强CPB的无侧限抗压强度（UCS）有显著提高，在3天、7天和28天时，平均UCS增长率分别为141.07%、57.62%和63.17%。宏观破坏模式和扫描电子显微镜分析表明，在拔出和拉脱破坏模式下，纤维可防止大的拉伸和剪切裂缝形成。建立了3天养护龄期UCS的线性拟合函数以及7天和28天养护龄期UCS的两个多项式拟合函数，以表征纤维增强和未增强CPB的UCS之间的关系。此外，基于复合材料力学，得到了与UCS和纤维增强指数相关的非线性模型。包含由纤维含量和纤维长径比组成的纤维增强指数的估计函数，可用于评估UCS。此外，纤维增强指数量化了纤维的增强作用。两种估计结果均表明，本研究中在3天、7天和28天养护龄期对UCS值的估计准确。此外，估计模型可用于指导纤维增强CPB的强度设计。除此之外，结果表明纤维增强CPB可在矿山充填中更广泛地应用，并满足可控低强度材料（CLSM）更广泛应用的要求。
