Improved hydration and properties of magnesium oxysulfate (MOS) cement using sodium silicate as an additive
Improved hydration and properties of magnesium oxysulfate (MOS) cement using sodium silicate as an additive
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DOI：
10.1016/j.conbuildmat.2020.120988
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发表时间：
2020-10
影响因子：
7.4
通讯作者：
M. Ba;Qing-Yuan Gao;Yanling Ma;Jiezhao Zhu;Yingang Du
中科院分区：
文献类型：
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作者：
M. Ba;Qing-Yuan Gao;Yanling Ma;Jiezhao Zhu;Yingang Du
氧硫酸镁（MOS）水泥具有早期强度高、导热系数低、耐燃、耐腐蚀性能优异等优点。但其强度不稳定，耐水性较差，限制了其在土木工程中的广泛应用。本研究首先制备了不同水玻璃掺量的MOS水泥试样，然后进行了分散试验、强度试验、SEM、XRD和等温量热分析等一系列室内试验，以评价改性后的MOS水泥的性能。实验结果表明，SS的增加持续降低了MOS水泥浆体的初凝时间、分散性和流动性性能，这是由于SS加速了MOS水化过程中的吸热反应。SS的加入量达到MgO质量的0.5%，可以显著提高MOS水泥的长期强度和耐水性。这是由于SS增强了硬化MOS膏体的微观结构，细化了硬化MOS膏体的粗孔，从而形成了致密得多的膏体，尽管它没有改变硬化MOS水泥中水化相组成的类别。
Magnesium oxysulfate (MOS) cement has many advantages, such as high early strength, low thermal conductivity, excellent fire and corrosion resistance. However, its strength is less stable and its water resistance is relatively poor, which limits its wide use in civil engineering. In this study, the MOS cement specimens with different amount of sodium silicate (SS) as an additive were manufactured before subjected to a series of laboratory tests, including dispersion tests, strength tests, SEM, XRD and Isothermal Calorimetry analysis to evaluate their modified properties. The experimental results show that an increase of the amount of SS consistently reduces the initial setting time, dispersion and fluidity performance of MOS cement paste because of the SS accelerated endothermic reaction during hydration process of MOS. An addition of the amount of SS up to 0.5% of the mass of MgO significantly increases the long-term strength and water resistance of MOS cement. This attributes to the fact that SS enhances microstructure and refines the coarse pores of hardened MOS paste, and thus forms much denser paste, although it does not change the category of hydration phase composition in hardened MOS cement.