组成和温度对重构钢渣结构及早期水化活性的影响

Effect of Composition and Temperature on Structure and Early Hydration Activity of Modified Steel Slag

关键词:  转炉钢渣  重构钢渣  水化活性

Key words:  basic oxygen furnace steel slag(BOFSS)  modified steel slag(MSS)  hydration activity

摘要:

在转炉钢渣中添加电炉渣和粉煤灰，通过重新加热来模拟炉外高温重构过程，运用岩相、XRD、强度试验及水化热测定等手段，研究了重构钢渣的组成、结构及其胶凝性能.结果显示：随着粉煤灰的增加，重构钢渣中硅酸盐矿物减少，而随着电炉渣的增多；其硅酸盐矿物增多;温度升高，低碱度重构钢渣硅酸盐矿物晶体尺寸增大，高碱度重构钢渣Alite矿增多，且矿物结构完整，游离氧化钙大幅减少.其中GB40 1350重构钢渣样品的3 d水化热相比于原钢渣增加1.9倍，GBF15 1350重构钢渣样品替代30%水泥熟料后的水泥净浆28 d抗压强度达到纯水泥净浆强度的99.9%.

Abstract:

The process that steel slag from electric arc furnace(EAFSS) and fly ash(FA) were incorporated into ordenary oxygen furnace steel slag(BOFSS) to reheat and modify its mineralogical composition and structure at high temperature was simulated in laboratory. The effect of composition and structure of modified BOFSS on its hydration activity was investigated. The mineralogical composition, microstructure and hydration activity of both BOFSS and modified steel slag(MSS) were investigated with X ray diffraction(XRD), optical microscopy, determination of compressive strength and isothermal calorimeter. The results show that after modification, the amount of silicate minerals in MSS is decreased with increasing use level of FA, whereas the amount of silicate minerals is increased with increasing use level of EAFSS. As a result, the crystal size of alite in MSS becomes bigger with low alkalinity, however, amount of alite in MSS with high alkalinity is increased, and morphology of alite in MSS is regular with much less free CaO. The cumulative hydration heat for sample GB40 1350 is greater than that for BOFSS by 1.9 times at 3 days, and the compressive strength of cement paste incorporating 30%(by mass) of ground sample GB40 1350 to replace cement reaches 99.9% of that for pure cement pastes at 28 days.