石英岩尾砂的表面改性及其对砂浆强度和干燥收缩的影响

Surface modification of quartz tailing and its effecton strength and drying shrinkage of cement mortars

采用电石渣对石英岩尾砂进行煅烧改性,利用X射线衍射仪、背散射扫描电镜和能谱分析等分析方法对改性石英岩尾砂矿物组成和微观结构进行表征,并测定了掺改性石英岩尾砂的水泥砂浆强度和干燥收缩。通过背散射扫描电镜和压汞仪研究了掺改性石英岩尾砂水泥砂浆的微观结构。结果表明,改性石英岩尾砂颗粒表面生成了具有水化活性的β-C_2S,水化生成CSH凝胶,可以改善石英岩尾砂与水泥浆体的界面结构,降低了水泥砂浆的孔隙率和干燥收缩,提高了掺改性石英岩尾砂水泥砂浆的抗压强度。

The surface of quartz tailing was modified by calcination method through mixing with carbide slag. The mineral composition and microstructure of the modified quartz tailing were analyzed by using X-ray diffrac-tion （XRD）,backscattered electron microscopy （BSEM）and energy dispersive spectrometer （EDS）.The effects of modified quartz tailing on the drying shrinkage and compressive strength of cement mortars were in-vestigated.The microstructure of cement mortars was analyzed by using BSEM and mercury intrusion porosim-etry （MIP）.The results show that theβ-C2 S phases were formed on the surface of the modified quartz tailings. Due to the hydration of theβ-C2 S,CSH gel was generated,the interface between cement paste and quartz tail-ing was densified,the porosity and drying shrinkage of cement mortars with the modified quartz tailing was de-creased,and the compressive strength of cement mortars was increased.