The Effect of Doping High Volume Magnesium Sulfate on Properties of Magnesium Oxychloride Cement

Crystals

Ying Li¹  Jing Wen²  Weixin Zheng²  Chenggong Chang²  Jinmei Dong²  Xueying Xiao²  Qing Huang³ 

[1] China Construction Fifth Engineering Bureau Co., Ltd., Changsha 410014, China;Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining 810008, China;School of Materials Science and Engineering, Shaanxi University of Technology, Hanzhong 723000, China;

关键词: magnesium oxychloride cement;    magnesium oxysulfate cement;    magnesium sulfate;    water resistance;    setting time;    compressive strength;   

DOI  :  10.3390/cryst12060857

来源: DOAJ

【 摘 要 】

The composite gelling system of chlorine and magnesium thioxide was prepared by mixing different mass fractions of magnesium sulfate solution into MOC. Detailed studies regarding the influences of magnesium sulfate replacing magnesium chloride on the setting time, compressive strength, and water resistance of magnesium oxychloride cement (MOC) have been carried out in this paper. The phase composition and micro morphology of the hydration products in the mixed system were analyzed by XRD and SEM. The results show that the addition of magnesium sulfate prolongs the setting time and reduces the compressive strength of the mixed MOC. Compared with the primordial MOC system, the water resistance of the mixed system improved, with the mixed system exhibiting optimal water resistance when the mass fraction of magnesium sulfate was 30%. The phases of the mixed system were composed of 5Mg(OH)₂·MgCl₂·8H₂O and 5Mg(OH)₂·MgSO₄·7H₂O phases. The microscopic morphology shows that the interior of air-cured MOC was composed of a large number of needle-like crystals, and continuous crystal structures have close contact and a strong bonding force. Cracks and pores appear on the surface after submerging in water, and the crystallization state of the internal crystals becomes worse. The compressive strength and water stability of MOC were closely related to the crystal morphology.

【 授权许可】

Unknown