In-situ XRD study of the temperature-dependent early hydration of calcium aluminate cement in a mix with calcite
In-situ XRD study of the temperature-dependent early hydration of calcium aluminate cement in a mix with calcite
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DOI：
10.1016/j.cemconres.2020.106160
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发表时间：
2020-10-01
影响因子：
11.4
通讯作者：
Goetz-Neunhoeffer, F.
中科院分区：
文献类型：
--
作者：
Goergens, J.;Manninger, T.;Goetz-Neunhoeffer, F.
本文用原位X射线衍射法研究了白钙土、惰性氧化铝填料和碳酸钙在不同温度下的水化行为。实验在10摄氏度、23摄氏度、40摄氏度和60摄氏度下进行。文献中经常描述通过向铝酸钙水泥中添加活性添加剂来克服或缓解铝酸钙水合物转化的现象。当加入足够量的方解石时，碳酸盐-原子力显微镜(单碳酸盐和半碳酸盐)有望成为主要的水合物相。方解石作为一种惰性填料，在10℃时几乎不影响铝酸钙的水化产物。随着温度的升高，单碳酸盐含量增加，水泥相的反应速度加快。在60℃时，早期水化过程中会析出少量的C(3)AH(6)。特别注意了CAH(10)和C(2)AH(X)在水化过程中的作用。在10℃时，CAH(10)占主导地位，而C(2)AH(X)在23-60℃的温度范围内析出，作为碳酸盐-AFM相的前驱相。在10℃时没有发现这些，这可能是由于缺乏前体相(C(2)AH(X))。M10℃和初始加入C(2)AH(X)的混合物的水化表明，除了CAH(10)之外，在最初的96h内还可以析出碳酸盐-AFM相。
In the present work the hydration of white CAC, inert alumina-filler and CaCO3 was investigated at different temperatures with in-situ XRD. Experiments were performed at 10 degrees C, 23 degrees C, 40 degrees C and 60 degrees C. Overcoming or mitigating the phenomena of calcium aluminate hydrate conversion by adding reactive additives to calcium aluminate cement is often described in literature. When a sufficient amount of calcite is added, carbonate-AFm (monocarbonate and hemicarbonate) is expected to be the dominant hydrate phase. Calcite however, acts as an inert filler and barely influences the calcium aluminate hydration products at 10 degrees C. With rising temperature monocarbonate contents increase as well as the reaction rate of cement phases. At 60 degrees C minor amounts of C(3)AH(6) precipitate during the early hydration. Special attention is given to the role of CAH(10) and C(2)AH(x) during hydration. While CAH(10) is dominant at 10 degrees C, C(2)AH(x) precipitates in a temperature range between 23 and 60 degrees C as a precursor phase for carbonate-AFm phases. These are not found at 10 degrees C, which is probably due to the lack of the precursor phase (C(2)AH(x)). The hydration of the mix M 10 degrees C with an initial addition of C(2)AH(x) shows that carbonate-AFm-phases can be precipitated in addition to CAH(10) during the first 96 h.