矿渣棉纤维长度与掺量对水泥基细尾砂充填体强度的影响

Influences of the Length and Content of Slag Cotton Fiber on the Strength of Cement-Based Fine Tailings Filling Body

为了研究矿渣棉纤维对细尾砂充填体强度特性的影响,开展压缩试验,探究了纤维长度、掺量和养护时间对充填体强度的影响规律,并结合结构损伤分析和微观图像对矿渣棉纤维的强度增强机理进行了探讨。结果表明:加入矿渣棉纤维使得试件的抗压强度增长,且在3~14 d养护龄期内充填体强度增长速度较快,14 d后趋于稳定;不同长度纤维对充填体强度的影响存在差异,中长纤维的强度增强效果最佳;随着纤维掺量的增加,强度指标呈现先增后减的现象,在纤维掺量为0.6%~0.8%时,强度达到最大值;当掺量过高时,纤维之间发生交缠和联结,形成团状聚集区,增加了充填材料内部局部区域的孔隙率,降低了试件抵抗变形的能力;矿渣棉纤维在胶结体中的桥接效应可抑制压缩裂缝的扩展,对试件破坏起到缓冲作用,从而增强了细尾砂充填体的强度性能。

In order to study the influence of slag cotton fiber on the strength characteristics of fine tailings filling body,the compression test was carried out to explore the influences of fiber length,content and curing time on the strength of filling body,and the strength enhancement mechanism of slag cotton fiber was discussed by combining structural damage analysis and microscopic image.The results show that the compressive strength of the specimens increases with the addition of slag cotton fiber,and the strength of the filling body increases rapidly during the curing period of 3-14 d,and tends to be stable after 14 d.The influence of different length fibers on the strength of filling body is different,and the strength enhancement effect of medium and long fibers is the best.With the increase of fiber content,the strength index increases first and then decreases.When the fiber content is 0.6%-0.8%,the strength reaches the maximum.When the content is too high,the fibers are entangled and connected to form a cluster aggregation area,which increases the porosity of the local area inside the filling material and reduces the ability of the specimen to resist deformation.The bridging effect of slag cotton fiber in the cemented body can inhibit the expansion of compression cracks and buffer the damage of the specimen,thus enhancing the strength performance of the fine tailings filling body.