Bimodal behavior of C-S-H interpreted from short-term length change and water vapor sorption isotherms of hardened cement paste
Bimodal behavior of C-S-H interpreted from short-term length change and water vapor sorption isotherms of hardened cement paste
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DOI：
10.1016/j.cemconres.2015.03.010
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发表时间：
2015-07-01
影响因子：
11.4
通讯作者：
Nishioka, Yukiko
中科院分区：
文献类型：
--
作者：
Maruyama, Ippei;Igarashi, Go;Nishioka, Yukiko
短期长度变化等温线（SLCI）和水蒸气吸附等温线是有用的，以消除胶体的C-S-H的特征的影响。硬化水泥浆体的SLCI最初条件下干燥到平衡，在不同的相对湿度（RH）进行了测量，在一个完整的RH循环5%和98%之间。基于从40%到98%RH的增量吸附厚度和增量应变之间的相关性，高于40%RH的C-S-H的基底间距似乎随着水蒸气吸附的增加而进一步增加。然而，没有发现这些值的相关性从5%至40%RH和基础间距被认为是稳定的，在这个领域。C-S-H的这些性质与其作为RH的函数的等温体积变化直接相关。可以得出结论，高于40%RH的主要收缩驱动因素是分离或水化压力，低于40%RH的主要收缩驱动因素是表面能的变化。(C)2015爱思唯尔有限公司版权所有。
Short-term length change isotherms (SLCIs) and water vapor sorption isotherms are useful to eliminate the effects of the colloidal features of C-S-H. SLCIs of hardened cement pastes initially conditioned by drying to equilibrium at different relative humidities (RHs) were measured over a complete RH loop between 5% and 98%. Based on the correlation between incremental thickness of adsorption and incremental strain from 40% to 98% RH, the basal spacing of C-S-H above 40% RH appears to increase further with increasing water vapor sorption. However, no correlation of these values was found from 5% to 40% RH and the basal spacing is considered stable in this domain. These properties of C-S-H are directly related to its isothermal volume change as a function of RH. It can be concluded that the dominant shrinkage driver above 40% RH is disjoining or hydration pressure and that below 40% RH is change in surface energy. (C) 2015 Elsevier Ltd. All rights reserved.