MgO-metakaolin cementitious materials: hydration, properties and microstructure

IF 10.8 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY

Cement & concrete composites Pub Date : 2025-07-24 DOI:10.1016/j.cemconcomp.2025.106256

Yongshan Tan , Xiangyi Cheng , Caijun Shi

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Abstract

MgO-metakaolin (MK) systems is a novel magnesium-based cementitious material that is a potential candidate for the solidification and encapsulation of radioactive waste. This study investigates the effects of the MgO/MK mass ratio, water-to-binder ratio, and curing age on the hydration, properties and microstructure of MgO-MK cementitious materials. The results suggest that increasing the MgO/MK mass ratio caused an enhancement in the compressive strength and flowability of MgO-MK cementitious materials and significantly reduced the total heat release of the MgO-MK system. The main hydration products found in the microstructure of the MgO-MK systems are brucite, hydrotalcite, and magnesium (aluminum) silicate hydrate gel (M-(A-)S-H), with the amorphous M-(A-)S-H gel being the primary hydration product. The amount of hydration products increased with an increase in the MgO content. Further, a significant reduction in the porosity of the samples were observed with an increase in the MgO/MK mass ratio resulting in a dense microstructure.

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镁偏高岭土胶凝材料：水化、性能及微观结构

镁-偏高岭土（MK）体系是一种新型镁基胶凝材料，是放射性废物固化和封装的潜在候选材料。研究了MgO/MK质量比、水胶比和养护龄期对MgO-MK胶凝材料水化、性能和微观结构的影响。结果表明，增加MgO/MK质量比，可以提高MgO-MK胶凝材料的抗压强度和流动性，显著降低MgO-MK体系的总放热量。MgO-MK体系微观结构的主要水化产物是水镁石、水滑石和硅酸镁（铝）水化凝胶（M-(A-)S-H），其中无定形的M-(A-)S-H凝胶是主要水化产物。水化产物的数量随MgO含量的增加而增加。此外，随着MgO/MK质量比的增加，观察到样品的孔隙率显著降低，从而产生致密的微观结构。

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来源期刊

Cement & concrete composites 工程技术-材料科学：复合

CiteScore

18.70

自引率

11.40%

发文量

459

审稿时长

65 days

期刊介绍： Cement & concrete composites focuses on advancements in cement-concrete composite technology and the production, use, and performance of cement-based construction materials. It covers a wide range of materials, including fiber-reinforced composites, polymer composites, ferrocement, and those incorporating special aggregates or waste materials. Major themes include microstructure, material properties, testing, durability, mechanics, modeling, design, fabrication, and practical applications. The journal welcomes papers on structural behavior, field studies, repair and maintenance, serviceability, and sustainability. It aims to enhance understanding, provide a platform for unconventional materials, promote low-cost energy-saving materials, and bridge the gap between materials science, engineering, and construction. Special issues on emerging topics are also published to encourage collaboration between materials scientists, engineers, designers, and fabricators.