改性5A沸石对偏高岭土地聚物微观结构及抗泛碱性能的影响

Effect of Modified 5A Zeolite on Microstructure and Efflorescence Resistance of Metakaolin Geopolymer

为了降低碱激发偏高岭土地聚物的泛碱程度,采用具备阳离子交换性能的改性5A沸石降低地聚物孔隙中游离碱金属阳离子的含量。通过地聚物的抗压强度测试、孔结构分析(BET)、微观形貌分析(SEM-EDS)等方法探究改性5A沸石对地聚物微观结构和宏观性能的影响。通过电感耦合等离子原子发射光谱仪(ICP-OES)检测浸出液中阳离子含量,利用Image Pro Plus软件计算在固定泛碱模式下地聚物的泛碱面积,评估改性5A沸石对地聚物泛碱程度的影响,并揭示改性5A沸石对地聚物中Na^(+)和Ca^(2+)迁移规律的影响。结果表明,掺量为4%(质量分数)的改性5A沸石既能通过内养护和微集料效应优化孔结构,增强地聚物的力学性能,又能与孔溶液进行阳离子交换,形成(N,C)-A-S-H凝胶;Na+浸出量降低了19.4%,地聚物表观泛碱程度降低了57.3%。

To reduce the degree of efflorescence in the alkali activation metakaolin geopolymer,modified 5A zeolite with cation exchange property was used to reduce the content of free alkali metal cations in the pores of geopolymer.The effect of modified 5A zeolite on the microstructure and properties of geopolymer were investigated by compressive strength test,pore structure analysis(BET)and SEM-EDS.The cation content in the leachate was detected by inductively coupled plasma optical emission spectrometer(ICP-OES),and the efflorescence area of geopolymer was calculated by Image Pro Plus software in the fixed efflorescence mode to evaluate the effect of modified 5A zeolite on the efflorescence degree of the geopolymer and reveal the effect of modified 5A zeolite on the migration patterns of Na^(+)and Ca^(2+)in geopolymer.The results show that the modified 5A zeolite with 4%(mass fraction)content can optimize the pore structure,enhance the mechanical properties of geopolymer through internal curing and micro-aggregate effect,and exchange cation in pore solution to form(N,C)-A-S-H gel.Na+leaching concentration reduces by 19.4%and the efflorescence area of geopolymer reduces by 57.3%.