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甲基硅酸钾改性磷石膏对水泥基湿拌砂浆力学性能的影响
作者：周远忠1，2，王宏杰2，陈鸿2，范勇2，范岭2，李杰2
（1.贵州师范大学 材料与建筑工程学院，贵州 贵阳 550025；2.贵州宇昆环保材料有限公司，贵州 贵阳 550081）
摘要：采用甲基硅酸钾对经石灰中和后的磷石膏进行表面改性，与水泥、机制砂、化学外加剂配制成湿拌砂浆，通过XRD及SEM分析改性磷石膏水泥基砂浆的矿物组成及微观形貌，考察甲基硅酸钾改性磷石膏对砂浆力学性能的影响。结果表明：甲基硅酸钾粘附在磷石膏晶体表面，部分阻断了水分子对磷石膏颗粒的溶蚀作用。与未掺甲基硅酸钾改性磷石膏相比，掺0.4%、0.6%甲基硅酸钾改性磷石膏中SO42-离子饱和浓度分别下降了40%和42%。甲基硅酸钾改性磷石膏对水泥中C3A水化反应的阻碍作用减弱，砂浆凝结时间缩短，出机稠度逐渐增大。掺0.4%、0.6%甲基硅酸改性磷石膏砂浆的28 d抗压强度分别为11.4、11.9 MPa，符合JC/T
230—2007《预拌砂浆》中WP M10强度等级要求。
关键词：甲基硅酸钾；磷石膏；水泥；湿拌砂浆
中图分类号：TU528.09 文献标识码：A 文章编号：1001-702X（2022）10-0123-05
Effects of phosphogypsum modified with potassium methyl silicate on mechanical properties of cement-based wet-mixed mortar
ZHOU Yuanzhong1，2，WANG Hongjie2，CHEN Hong2，FAN Yong2，FAN Ling2，LI Jie2
（1.School of Materials and Architectural Engineering，Guizhou Normal University，Guiyang 550025，China；
2. Guizhou Yukun Environmental Protection Building Material Co. Ltd.，Guiyang 550081，China）
Abstract：The lime-neutralized phosphogypsum was surface-modified with potassium methylsilicate，and mixed with cement，machine-made sand and chemical admixtures to make wet-mixed mortar. The hydration and hardening of the modified phosphogypsum cement-based mortar was analyzed by XRD and SEM. The mineral composition and microscopic morphology of the mortar were investigated，and the effect of potassium methylsilicate modified phosphogypsum on the mechanical properties of mortar was investigated. Results show that potassium methylsilicate adhered to phosphogypsum crystal surface and partially blocked the dissolution of phosphogypsum particles by water molecules. Compared with that without the addition of potassium methylsilicate，the saturated concentration of SO42- ions in the modified phosphogypsum with the content of 0.4% and 0.6% potassium methylsilicate decreased by 40% and 42%，respectively. The retarding effect of modified phosphogypsum on hydration reaction of C3A in cement is weakened，the setting time of mortars is shortened，and the consistency of mortars is increased gradually. When modified phosphogypsum with 0.4% and 0.6% potassium methylsilicate，the compressive strength of mortar is 11.4 MPa and 11.9 MPa after 28 days，which can meet the WP M10 strength requirements of the industrial standard JC/T 230—2007 "Pre-mixed mortar".
Key words：potassium methylsilicate，phosphogypsum，cement，wet-mixed mortar