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外加剂对硫氧镁水泥性能的影响及其机理研究
作者：冯叶1，朱建斌2，高至岭2，沃成昌2，顾金楼1
（1.华东理工大学 材料科学与工程学院，上海 200237；2.上海唐盾材料科技有限公司，上海 201203）
摘要：研究了柠檬酸、硅酸钠、磷酸、明矾、聚丙烯纤维等外加剂对硫氧镁水泥力学性能和耐水性的影响，并采用XRD、FT-IR、SEM等表征硫氧镁水泥的物相组成和微观形貌。结果表明：在改性硫氧镁水泥基体中出现了大量针杆状的5Mg（OH）2·MgSO4·7H2O（517相）硫氧镁晶体。在未掺聚丙烯纤维增强的情况下，以柠檬酸和明矾作为复合外加剂的改性效果最好，抗折、抗压强度和耐水性都大幅提高，并讨论了明矾的改性机理；硫氧镁水泥与聚丙烯纤维有较好的结合作用，为硫氧镁水泥增强改性提供了新思路。
关键词：硫氧镁水泥；明矾；力学性能；耐水性；微观结构
中图分类号：TU526 文献标识码：A 文章编号：1001-702X（2019）11-0131-05
Effects of addictive on magnesium oxysulfate cement and its mechanism
FENG Ye1，ZHU Jianbin2，GAO Zhiling2，WO Chengchang2，GU Jinlou1
（1.School of Materials Science and Engineering，East China University of Science and Technology，Shanghai 200237，China；
2.Shanghai Tangdun Material Technology Co.，Ltd，Shanghai 201203，China）
Abstract：In this paper，the effects of several addictives，such as citric acid，sodium silicate，phosphoric acid，alum and polypropylene fiber，on the mechanical properties and water resistance of magnesium oxysulfate cement were studied. The phase composition and microstructure of the hydration products were analyzed by XRD，FT-IR，and SEM. The results show that a large number of needle-shaped 5Mg（OH）2·MgSO4·7H2O（517 phase） crystals were formed in the modified magnesium oxysulfate cement. In the absence of fiber reinforcement，using citric acid and alum as compound additives had the best modification effect，and their flexural strength，compressive strength and water resistance were greatly improved，meanwhile，the modification mechanism of alum was discussed for the first time. In addition，it has been found that magnesium oxysulfate cement and polypropylene fiber had good binding ability，which provided a new idea for strengthening and modifying magnesium oxysulfatecement.
Key words：magnesium oxysulfate cement，alums，mechanical properties，water resistance，microstructure