微硅粉改性磷酸镁水泥砂浆试验研究

Effect of Silica Fume on Properties of Magnesium Phosphate Cement Mortar

摘要:

以过烧镁砂和磷酸二氢铵为主要原料，掺入少量微硅粉和石英砂来制备磷酸镁水泥（MPC）砂浆，研究了微硅粉掺量对磷酸镁水泥砂浆性能的影响，并采用X射线衍射（XRD）和扫描电镜（SEM）等对其水化产物进行分析.结果表明：随着微硅粉掺量的增加，磷酸镁水泥砂浆的凝结时间和流动性呈下降趋势，而早期强度先增后减；微硅粉的掺入可大幅提高磷酸镁水泥砂浆的耐水性；微硅粉的掺入大幅提高了磷酸镁水泥砂浆水化产物结构的密实性，同时生成了麻花状硅酸镁晶体，该晶体将鸟粪石和未反应的MgO连接在一起，提升了磷酸镁水泥砂浆的力学性能和耐水性.

Abstract:

Magnesium phosphate cement(MPC) mortar can be mass produced with proportioned dead burned magnesite and ammonium dihydrogen phosphate as main raw materials and adding silica fume and sand. The effect of some performance of silica fume on properties of MPC were studied. The hydration products were analyzed and discussed by XRD and SEM. The results show that the setting time and fluidity decrease with the addition of silica fume. However, the early strength increases first and then decreases with the addition of silica fume, and the water resistance is improved greatly. Magnesium silicate is formed in the twist form, which improve the properties of the magnesium phosphate cement matrix by increasing the compactness and joining struvite and unreacted MgO together.