The hydration, strength and deformation of Portland composite cements containing light-burnt dolomite and metakaolin

IF 1.4 4区工程技术 Q3 CONSTRUCTION & BUILDING TECHNOLOGY

Advances in Cement Research Pub Date : 2022-07-20 DOI:10.1680/jadcr.21.00141

Deng Chen, L. Mo, A. Wang, Kaiwei Liu, Shiping Zhang, Tao Yang

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Abstract

Light-burnt dolomite (LBD) as a compound MgO expansive agent can compensate effectively the shrinkage of concrete at early ages. However, in terms of strength, the replacement amount of Portland cement with LBD is limited due to the low reactivity of calcite in LBD. In this study, metakaolin used as a modified material was incorporated into the blended cements containing LBD to improve the reactivity of calcite in LBD. The results showed that the incorporation of LBD and metakaolin decreased the hydration heat and strengths of Portland cement at early ages, but the strength increased with increasing the mass ratio of metakaolin to LBD at later ages. Especially, the strengths of the blended cement containing 20% metakaolin and 20% LBD were even higher than those of Portland cement. This was mainly related to the formation of compact pore structure with decreased porosities due to the improvement of the reactivity of calcite in LBD and the pozzolanic reactivity of metakaolin. Additionally, in comparison to Portland cement, the incorporation of LBD and metakaolin could produce a certain expansion due to the high hydration reactivity of MgO in LBD, and mitigated the shrinkage.

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轻烧白云石和偏高岭土硅酸盐复合水泥的水化、强度和变形

轻烧白云石（LBD）作为复合MgO膨胀剂，能有效补偿混凝土早期收缩。然而，就强度而言，由于LBD中方解石的低反应性，LBD对硅酸盐水泥的替代量是有限的。在本研究中，将偏高岭土作为改性材料掺入含有LBD的混合水泥中，以提高LBD中方解石的反应性。结果表明，LBD和偏高岭土的掺入降低了硅酸盐水泥早期的水化热和强度，但后期强度随着偏高岭土与LBD质量比的增加而增加。特别是含有20%偏高岭土和20%LBD的混合水泥的强度甚至高于硅酸盐水泥。这主要与由于LBD中方解石的反应性和偏高岭土的火山灰反应性的提高而形成的孔隙率降低的致密孔结构有关。此外，与硅酸盐水泥相比，由于LBD中MgO的高水化反应性，LBD和偏高岭土的掺入可以产生一定的膨胀，并减轻收缩。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Advances in Cement Research 工程技术-材料科学：综合

CiteScore

3.70

自引率

5.00%

发文量

审稿时长

3.2 months

期刊介绍： Advances in Cement Research highlights the scientific ideas and innovations within the cutting-edge cement manufacture industry. It is a global journal with a scope encompassing cement manufacture and materials, properties and durability of cementitious materials and systems, hydration, interaction of cement with other materials, analysis and testing, special cements and applications.