Hydration properties of modified magnesium slag-based composite cementitious materials for mining

被引：0
|
作者：
Sun W. [1 ,2 ]
Liu L. [1 ,2 ]
Xu L. [3 ]
Fang Z. [1 ,2 ]
Ruan S. [1 ,2 ]
Hou D. [4 ]
机构：
[1] Energy School, Xi'an University of Science and Technology, Xi'an
[2] Mine Functional Backfill Technology Research Center, Xi'an University of Science and Technology, Xi'an
[3] MOE Key Laboratory of Solid Waste Treatmentand Resources Recycle, Southwest University of Science and Technology, Mianyang
[4] College of Geology and Environment, Xi'an University of Science and Technology, Xi'an
来源：
Zhongnan Daxue Xuebao (Ziran Kexue Ban)/Journal of Central South University (Science and Technology) | 2022年 / 53卷 / 10期
基金：
中国国家自然科学基金;
关键词：
composite cementitious material; hydration characteristics; modified magnesium slag (MMS); synergistic reaction;
D O I：
10.11817/j.issn.1672-7207.2022.10.025
中图分类号：
学科分类号：
摘要：
In order to realize low cost and green filling, safe disposal and resources utilization of solid waste from magnesium slag in magnesium enterprises and fly ash from coal-fired power plants, a type of mine filling cementing material (MSCM) was prepared by mixing modified magnesium slag (MMS) and fly ash (FA) as a substitute for portland cement. Firstly, the physical and chemical properties of MMS and FA were analyzed. Then, the microstructure, hydration characteristics and macroscopic strength of MSCM were analyzed by microcalorimetry, X-ray diffraction test, infrared spectroscopy test, thermogravimetric test, uniaxial compressive strength test and scanning electron microscope. The results show that the optimal mass ratio of MMS to FA is 4:1 (FA20 sample), and the compressive strength of curing for 3 d and 28 d is 1.50 MPa and 5.64 MPa, respectively, which is 57% and 21% higher than that of modified magnesium slag slurry sample. The hydration products of MSCM are mainly C-S-H gel, ettringite and Ca(OH)2. With the hydration reaction going on, the number of hydration products increases significantly, and they stagger each other and closely agglomerate, making their internal microstructure more dense. Moreover, ettringite gradually changes from needle-like to rod-like at the initial hydration stage, which is more helpful to the development of sample strength. The addition of FA has a significant effect on the hydration of MSCM, effectively shortening the reaction time of MSCM in the hydration acceleration stage and improving the overall hydration reaction rate. This is also the result of the co-hydration reaction between MMS and Al2O3 and SiO2 in FA. © 2022 Central South University of Technology. All rights reserved.
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页码：4057 / 4070
页数：13
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