铁尾矿砂-地聚物复合材料的界面与性能

Interface and Performance of Iron Tailings-Geopolymer Composites

用铁尾矿砂或天然砂配制水泥/地聚物砂浆,并对不同骨料与基体间界面的化学反应、界面过渡区(ITZ)微观结构及砂浆性能进行对比研究.结果表明:掺加铁尾矿砂后,粉煤灰/矿渣地聚物溶液中的Na^(+)、Si^(4+)、Al^(3+)、Ca^(2+)质量浓度均有不同程度降低,其中矿渣地聚物溶液反应速率较快,对骨料表层溶解也有更强的促进作用;铁尾矿砂附近界面过渡区结构明显优于天然河砂,且铁尾矿砂-地聚物砂浆的界面纳米力学性能显著高于铁尾矿砂-水泥砂浆;用铁尾矿砂制备的砂浆强度及抗渗性也均优于天然河砂,这种差异在水泥砂浆中最小,在矿渣地聚物砂浆中最显著,而粉煤灰地聚物砂浆在后期才逐渐凸显出铁尾矿砂的优势.

Iron tailings and natural sand were used to prepare cement/geopolymer mortar.The chemical reaction between the fine aggregate and the matrix,microstructure of interfacial transition zone(ITZ),strength and impermeability of mortars were studied.The results show that the mass concentrations of Na^(+),Si^(4+),Al^(3+)andCa^(2+)in both geopolymer solutions decrease after adding iron tailings powder.The reaction rate in the slag-based geopolymer solution is faster,it plays a stronger role in promoting effect on the dissolution of surface layer of aggregate.The structure of ITZ near the iron tailings is obviously better than that of natural sand,especially in geopolymer mortar.The interfacial nanomechanical performance of iron tailing-geoploymer are significantly higher than that of iron tailing-cement mortar.The strength and impermeability of iron tailings mortar are also better than that of natural sand mortar.The difference is the smallest for cement mortar,and the most significant for slag-based geopolymer mortar,while for the fly ash-based geopolymer mortar the advantage of iron tailings can be seen only in the later stage.