Matthew Zhi Yeon Ting, Bo Xu, Mingqian Yang, Yaolin Yi
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引用次数: 0
Abstract
Excessive ettringite formation degrades cementitious binders. Ground granulated blastfurnace slag (GGBS) can alleviate the damage, but ettringite development remains inevitable in sulphate-rich environments. This study explores MgO to suppress ettringite formation in GGBS. Ettringite content, evolution, and characteristics were evaluated in MgO-GGBS with inherent, internal, and external sulphates, and compared to GGBS and CaO-GGBS. To simulate internal sulphate, 1 %–5 % Na2SO4 was introduced before hydration; for external sulphate, hardened specimens were immersed in 5 % Na2SO4 solution. With inherent sulphate, GGBS formed ettringite within 0.5 h; CaO-GGBS gradually converted ettringite to monosulfate, whereas MgO-GGBS inhibited ettringite by 60 %–80 %. 1 %–5 % internal sulphate increased ettringite in CaO-GGBS since monosulfate was transitioned to ettringite, whereas MgO-GGBS showed 45 %–85 % less ettringite. Under external sulphate, MgO-GGBS produced 62 %–72 % less ettringite. This was attributed to Al-immobilizing phases and low Mg(OH)2 solubility; hydrotalcite in MgO-GGBS intercalated sulphate. This study indicates MgO-GGBS as promising binders for sulphate-rich environments.
期刊介绍:
Cement and Concrete Research is dedicated to publishing top-notch research on the materials science and engineering of cement, cement composites, mortars, concrete, and related materials incorporating cement or other mineral binders. The journal prioritizes reporting significant findings in research on the properties and performance of cementitious materials. It also covers novel experimental techniques, the latest analytical and modeling methods, examination and diagnosis of actual cement and concrete structures, and the exploration of potential improvements in materials.