The influence of low calcium sulfate contents on early calcium aluminate cement–calcite hydration kinetics and pore solution chemistry

IF 10.9 1区工程技术 Q1 CONSTRUCTION & BUILDING TECHNOLOGY Cement and Concrete Research Pub Date : 2024-07-23 DOI:10.1016/j.cemconres.2024.107615

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Abstract

A binder mix consisting of CAC, calcite and H₂O was investigated to clarify the influence of the addition of low amounts of calcium sulfate in the form of gypsum, hemihydrate or anhydrite on the hydration at 23 °C. Based on experimental data, a model for the hydration of CAC + calcite in the presence of sulfate ions could be developed. Using heat flow calorimetry at 23 °C, it was shown that hydration is accelerated depending on the solubility rates of the different sulfates. In addition, early hydration is characterized by a sequential reaction in which the calcium sulfate must be consumed completely from the pore solution by the precipitation of ettringite before the already known course of CAC + Cc hydration can occur. Monocarbonate and AH₃ precipitate as the stable dominant hydrate phases during the main reaction, but conversion-sensitive hydrate phases such as CAH₁₀ are not stable.

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低硫酸钙含量对早期铝酸钙水泥-方解石水化动力学和孔溶液化学性质的影响

研究了一种由 CAC、方解石和 HO 组成的粘结剂混合物，以明确添加少量石膏、半水合物或无水石膏形式的硫酸钙对 23 °C 下水合作用的影响。根据实验数据，可以建立 CAC + 方解石在硫酸根离子存在下的水合模型。利用 23 °C 下的热流量热法，结果表明水化加速取决于不同硫酸盐的溶解速率。此外，早期水化的特点是顺序反应，即在已知的 CAC + Cc 水化过程发生之前，孔隙溶液中的硫酸钙必须通过乙长石的沉淀完全消耗掉。在主要反应过程中，单碳酸盐和 AH 沉淀为稳定的主要水合物相，但 CAH 等对转化敏感的水合物相并不稳定。

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来源期刊

Cement and Concrete Research 工程技术-材料科学：综合

CiteScore

20.90

自引率

12.30%

发文量

318

审稿时长

53 days

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.