高温干燥养护时间对铁尾矿基水泥胶砂力学性能的影响

为探究高温干燥养护时间对铁尾矿基水泥胶砂强度的影响，研究了不同铁尾矿粉磨时间下干燥养护时间对试件力学性能的影响，并结合XRD、SEM及EDS等微观手段分析水化产物种类、数量及结构特征。结果表明：①60 ℃干养可激发铁尾矿的火山灰活性，试件的力学性能与养护时间成正比。掺加粉磨时间1 h的铁尾矿，在60 ℃的温度下干养16 h可得到抗折、抗压强度达9.29 MPa、40.46 MPa的铁尾矿基水泥胶砂。②高温干养时长不影响铁尾矿基水泥净浆的水化产物种类，但是对水化产物的结构与数量以及水化产物覆盖程度有影响。随着高温干养时间的延长，净浆内部C—S—H纤维长度增加、数量增多，钙硅摩尔比减小，Ca(OH)2消耗更剧烈，水化产物明显变密实，表面几乎不含有害孔。

Influence of High Temperature Drying Curing Time on the Mechanical Properties of Iron Tailings-based Cement Mortar

In order to explore the effect of drying curing time at high temperature on the strength of iron tailing cement mortar,the effect of drying curing time on the mechanical properties of specimens under different iron tailing grinding time was studied,and the types,quantity and structural characteristics of hydration products were analyzed by XRD,SEM and EDS.The results showed that∶① Pozzolanic activity of iron tailings can be stimulated by dry curing at 60 ℃,and the mechanical properties of specimens are directly proportional to curing time.Adding iron tailings with grinding time of 1 h and dry curing at 60 ℃ for 16 h,the flexural strength and compressive strength of iron tailings cement mortar can reach 9.29 MPa and 40.46 MPa.② High temperature dry curing time has no effect on the types of hydration products of iron tailing cement slurry;but has an effect on the structure and quantity of hydration products and the coverage degree of hydration products.With the increase of dry curing time at high temperature,the length and quantity of C—S—H fiber increased,the value of Ca/Si decreased,the consumption of Ca(OH)2 became more intense,and the hydration products became denser obviously with almost no harmful pores on the surface.