纳米偏高岭土对粉煤灰水泥砂浆强度及氯离子渗透性的影响

Effect of nano-metakaolin on strength and chloride penetration properties of fly ash-cement mortar

为探明纳米偏高岭土(NMK)对粉煤灰(FA)水泥砂浆流动度、强度及氯离子渗透性的影响,采用跳桌法测试粉煤灰-纳米偏高岭土(FA-NMK)水泥砂浆的流动度,利用快速氯离子迁移系数法(RCM法)测定其氯离子渗透系数;通过场发射扫描电镜(SEM)从微观尺度观测NMK对水化过程中FA水泥砂浆微观形貌的影响,依据砂浆内部微观形貌的演变过程揭示其宏观性能的发展规律。结果表明:NMK降低了FA砂浆的流动性,提高FA砂浆抗氯离子渗透性及抗压、抗折强度;SEM分析结果显示,NMK使粉煤灰砂浆内部水化产物增多,微观结构更加密实。

The effects of nano-metakaolin(NMK)on the strength and chloride ion permeability of fly ash(FA)mortar were studied.The fluidity of cement mortar with the addition of NMK and FA was tested by jumping table method.The rapid chloride ion migration coefficient method(RCM)was applied to examine its chloride ion permeability coefficient.The effect of NMK on the microscopic morphology of fly ash mortar during the hydration process was observed by field emission scanning electron microscopy(SEM).The relation between the evolution process of the morphology and its macroscopic properties was discussed.It is shown that NMK reduces the fluidity of FA mortar,while improves its chloride ion permeability and strength.SEM analysis results proved that NMK increases the hydration products,and the microstructure compactness is largely improved.