Improved model for capillary absorption in cementitious materials: Progress over the fourth root of time
Improved model for capillary absorption in cementitious materials: Progress over the fourth root of time
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DOI：
10.1016/j.cemconres.2017.07.003
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发表时间：
2017-10-01
影响因子：
11.4
通讯作者：
De Belie, Nele
中科院分区：
文献类型：
--
作者：
Villagran Zaccardi, Yury A.;Alderete, Natalia M.;De Belie, Nele
吸附率被广泛用于表征胶凝材料的孔隙连通性，并应用于耐久性设计。吸水系数（WSC）通常由吸水量与t（0.5）之比得到。然而，对于胶凝材料，这种关系不是线性的，并且在计算时需要约定。文献中不同的标准使WSCs的比较复杂化。本文提出了一种描述整个吸收过程的新方法。我们证实了硅酸钙水合物的吸湿性和过程中的溶胀效应是胶凝材料异常毛细血管吸收的主要原因。我们提出了一个理论模型，其中毛细管吸收的单一描述系数随t（0.25）线性增长。该模型与实验数据拟合良好，解决了t（0.25）缺乏线性的问题。然后提供传输过程的完整描述。
Sorptivity is broadly used for characterising the pore connectivity of cementitious materials, with applications in design for durability. A water sorptivity coefficient (WSC) is typically obtained from the ratio between the amount of absorbed water and t(0.5). This relationship is however not linear for cementitious materials, and conventions are needed for the computation. Variable criteria in the literature complicate the comparison of WSCs. This paper proposes a new approach for describing the entire absorption process. We substantiate the hygroscopicity of calcium silicate hydrates and the effect of swelling during the process as the main causes for the anomalous capillary absorption by cementitious materials. We present a theoretical model with a single descriptive coefficient of capillary absorption progressing linearly with t(0.25). The model fits remarkably well to experimental data, and it solves the problem of lack of linearity with t(0.25). A full description of the transport process is then offered.