Creep behavior of C-S-H under different drying relative humidities: Interpretation of microindentation tests and sorption measurements by multi-scale analysis
Creep behavior of C-S-H under different drying relative humidities: Interpretation of microindentation tests and sorption measurements by multi-scale analysis
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DOI：
10.1016/j.cemconres.2020.106036
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发表时间：
2020-06
影响因子：
11.4
通讯作者：
P. Suwanmaneechot;A. Aili;I. Maruyama
中科院分区：
文献类型：
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作者：
P. Suwanmaneechot;A. Aili;I. Maruyama
混凝土徐变背后的机制主要受水合硅酸钙 (C-S-H) 的控制。本研究的结果证明了不同的相对湿度、水灰比和水泥类型对通过微压痕测定的硬化水泥浆体的蠕变性能的影响。水蒸气吸附和 XRD/Rietveld 分析用于表征测试的水泥浆样品。还应用多尺度分析将水泥浆体的蠕变特性降低到 C-S-H 凝胶的蠕变特性。当干燥相对湿度降低时，C-S-H凝胶的比表面积降低，而体积模量增加。蠕变模量的增加可以通过水分子润滑的 C-S-H 片材的滑动来解释。干燥降低了比表面积，导致C-S-H片滑动困难增加；因此，蠕变模量增加。
The mechanism behind the creep of concrete is primarily governed by calcium silicate hydrate (C-S-H). The results presented in this study demonstrate the effect of varying relative humidity, water-to-cement ratios, and cement type on the creep properties of hardened cement paste as determined by microindentation. Water vapor sorption and XRD/Rietveld analysis were used to characterize the tested cement paste samples. Multi-scale analysis was also applied to downscale the creep properties of the cement paste to that of the C-S-H gel. When the drying relative humidity decreased, the specific surface area decreased whereas the bulk modulus of the C-S-H gel increased. This increase of creep modulus may be explained by the sliding of C-S-H sheets as lubricated by water molecules. Drying reduces the specific surface area, resulting in increased difficulty in the sliding of C-S-H sheets; hence, the creep modulus increases.