Calcined clays, combined with limestone, exhibit significant potential as SCMs for achieving high clinker substitution levels. This is partly related to their high aluminum and silicon contents. Binary Portland cement – calcined clay (PC2) blends and ternary blends with limestone (LC3) have been examined using metakaolin (MK) as calcined clay for blends with low and high MK/clinker ratios. The hydration reactions (up to 420 days) and aluminum distribution within the C-(A)-S-H and calcium aluminate hydrate phases have been quantitatively assessed by 27Al and 29Si NMR spectroscopy. The presence of limestone induces higher amounts of ettringite in the LC3 blends, resulting in lower amounts of Al(4) in the C-(A)-S-H. For the high MK/clinker ratio blends, the increase of aluminum incorporated in the C-(A)-S-H phase after prolonged hydration coincides with a leveling off for the amount of AFm phases for the binary and ternary blends at 60 % and 40 % of MK reaction, respectively.

中文翻译：

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通过 27Al 和 29Si NMR 波谱研究了波特兰水泥-偏高岭土-石灰石混合物的 C-（A）-S-H 和铝酸钙水合物相中的铝分布


煅烧粘土与石灰石相结合，在实现高熟料替代水平方面具有巨大的潜力。这部分与它们的高铝和硅含量有关。二元波特兰水泥-煅烧粘土 （PC2） 混合物和三元混合物与石灰石 （LC3） 已经使用偏高岭土 （MK） 作为低 MK/熟料比的混合物的煅烧粘土进行了研究。C-（A）-S-H 和铝酸钙水合物相中的水合反应（长达 420 天）和铝分布已通过 27Al 和 29Si NMR 波谱定量评估。石灰石的存在在 LC3 混合物中诱导出更多的钙矾石，导致 C-（A）-S-H 中 Al（4） 的含量较低。对于高 MK/熟料比共混物，长时间水化后 C-（A）-S-H 相中掺入铝的增加与二元和三元共混物的 AFm 相量分别在 MK 反应的 60 % 和 40 % 时趋于平稳。