粉煤灰在磷酸镁水泥体系中的作用机制研究  

Study on the Mechanism of Fly Ash in Magnesium Phosphate Cement

作　　者：孟祥瑞 刘源涛 陈兵[1,2] 王立艳[3] MENG Xiangrui;LIU Yuantao;CHEN Bing;WANG Liyan(State Key Laboratory of Ocean Engineering,Shanghai Jiao Tong University,Shanghai 200240,China;Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure,Shanghai Jiao Tong University,Shanghai 200240,China;School of Materials Science and Engineering,Jilin Jianzhu University,Changchun 130118,China)

机构地区：[1]上海交通大学海洋工程全国重点实验室,上海200240 [2]上海交通大学上海市公共建筑和基础设施数字化运维重点实验室,上海200240 [3]吉林建筑大学材料科学与工程学院,长春130118

出　　处：《材料导报》2024年第17期25-31,共7页Materials Reports

基　　金：国家自然科学基金(52278265);吉林省科技发展计划项目(20220203080SF)。

摘　　要：本工作采用粉煤灰(Fly ash,FA)替代一部分(≤30%)氧化镁对磷酸镁水泥(MPC)砂浆进行改性,研究了粉煤灰在MPC体系中的活性和作用机制,分析了FA对MPC物理力学性能和微观结构的影响。结果显示,FA在MPC体系中体现了复杂的物理和化学效应。球形粉煤灰颗粒具有滚动轴承的功能,优化了MPC的流动性;FA不仅填充了MPC的微孔隙、微裂缝,还体现了“晶核效应”,为MPC水化提供了成核位点,促进水化产物鸟粪石(MgNH_(4)PO_(4)·6H_(2)O)的生成,使MPC的微观结构变得致密,从而提高了MPC的力学性能。此外,在水化热激活下,FA中的Al_(2)O_(3)会参与反应,生成少量磷酸铝相无定型凝胶。Fly ash(FA)was applied to modify magnesium phosphate cement(MPC)mortar by replacing a portion(≤30%)of magnesium oxide,and the reactivity and reaction mechanism of fly ash in the MPC system were investigated,the effect of FA on the physico-mechanical properties and microstructure of MPC was analyzed.The results showed that FA embodied complex physical and chemical effects in the MPC system.The spherical fly ash particles have the function of rolling bearings,which optimizes the fluidity of MPC;FA not only fills the micropores and microcracks of MPC,but also exhibits the‘nucleating effect’,which provides nucleation sites for the hydration of MPC,promotes the generation of the hydration product-struvite(MgNH_(4)PO_(4)·6H_(2)O),densifies the microstructure and improves the mechanical properties of MPC.In addition,after the activation of hydration heat,Al_(2)O_(3)from FA would participate in the reaction and generate amorphous aluminum phosphate gels.

关 键 词：磷酸镁水泥 粉煤灰 作用机制 工作性 力学性能 

分 类 号：TQ172[化学工程—水泥工业]