铁尾矿基多元体系抗压强度及水化特性研究

Study on the Compressive Strength and Hydration Properties of Multicomponent Admixture Based on Iron Tailings

以铁尾矿、磷渣、脱硫灰为复合掺和料部分替代水泥,确定掺量为30%的情况下,考察复合掺和料不同配比对水泥砂浆试件抗压强度的影响,采用扫描电镜(SEM)和热重-差示扫描量热(TG-DTG)分析了水化产物数量及微观结构。结果表明,当铁尾矿、磷渣、脱硫灰质量比为1∶2∶2时强度最佳,7 d和28 d强度分别达到24.2 MPa和34.6 MPa。复合掺和料体系中,铁尾矿活性较低,主要起到微集料填充效应,使体系颗粒级配均匀;磷渣、脱硫灰中活性SiO_(2)、Al_(2)O_(3)可以通过二次水化反应进一步为体系提供强度,三者存在耦合效应,协同水化,生成水化硅酸钙(C-S-H)等水化产物促进强度提升。

Iron tailings,phosphorus slag and desulfurized ash were used as composite admixtures to partially replace cement,and the effect of different proportions of composite admixtures on the compressive strength of cement mortar specimens was investigated when the content was determined to be 30%.The amount and microstructure of hydration products were analyzed by means of scanning electron microscopy(SEM)and thermogravimetric analysis(TG-DTG).The results show that when the mass ratios of iron tailings,phosphorus slag and desulfurization ash are 1∶2∶2,the strength is the best.The 7 d and 28 d strengths reach 24.2 MPa and 34.6 MPa respectively.In the composite admixture system,the activity of iron tailings is relatively low,which mainly plays the role of micro aggregate filling,making the particle size grading of the system uniform;Active SiO_(2) and Al_(2)O_(3) in phosphorous slag and desulfurization ash can further provide strength for the system through secondary hydration reaction.The three admixtures have a coupling effect,and generate hydration products such as C-S-H to promote the strength.