纤维加筋高钙地聚物固化高黏尾砂的强度特性及机制分析

Strength characteristics and mechanism analysis of fiber reinforced highly cohesive tailings solidified using high-calcium geopolymer

高黏尾砂固化处理是其资源化利用的重要手段之一。以高黏铁尾砂为对象,开展了高钙地聚物固化尾砂的强度特性试验,分析了玄武岩纤维掺量和干湿循环对固化体强度的影响。围绕固化体的微观胶结行为、无侧限抗压强度、干湿侵蚀响应参数(强度、质量损失、电化学指标)展开讨论,试验发现:(1)纤维加筋增大了强度,0.5%为最优掺量(强度提升29.1%),相当于降低约2%的固化剂用量;(2)纤维-水化产物-尾砂以胶结和摩擦咬合作用相结合,适量纤维导致颗粒间产生微细孔隙,微孔隙的存在增加了持水能力;(3)干湿循环破坏胶结作用,6级循环后达到稳定,纤维对提升固化体抗干湿性不显著。以上成果为弄清固化尾砂强度演化机制及耐久性提供了理论支撑和方法借鉴。

Solidification treatment of highly cohesive tailings is one of the important means for resource utilization.Highly cohesive iron tailings were taken as the object to carry out strength characteristic experiments of solidified tailings using high-calcium geopolymer to analyze the impacts of different dosages of chopped basalt fiber and dry-wet cycles.The micro-cementation behavior,unconfined compressive strength,and the response parameters after dry-wet cycles(strength,mass loss,and electrochemical properties)of the fiber-reinforced solidified materials were discussed.It is concluded that:1)Adding fiber increased the strength.0.5%was the optimal dosage(strength increased by 29.1%),which is equivalent to reducing the dosage of geopolymer by about 2%.2)Fiber,hydration products and tailings were bonded by cementation and frictional occlusion.An appropriate amount of fiber could reduce pore connectivity and increase the capillary water holding capacity.3)The dry-wet cycles destroyed the cementation,and the damage was stable after the sixth cycle.The fiber has no obvious advantage in improving the dry-wet durability of the solidified materials.The above results provide theoretical support and method reference for clarifying the strength characteristics and durability of solidified tailings.