Centro de Fisica de Materiales (CSIC, UPV∕EHU), Paseo Manuel de Lardizabal 5, 20018, San Sebastián, Spain.
J Chem Phys. 2011 Jan 21;134(3):034509. doi: 10.1063/1.3521481.
The behavior of water dynamics confined in hydrated calcium silicate hydrate (C-S-H) gel has been investigated using broadband dielectric spectroscopy (BDS; 10(-2)-10(6) Hz) in the low-temperature range (110-250 K). Different water contents in C-S-H gel were explored (from 6 to 15 wt%) where water remains amorphous for all the studied temperatures. Three relaxation processes were found by BDS (labeled 1 to 3 from the fastest to the slowest), two of them reported here for the first time. We show that a strong change in the dielectric relaxation of C-S-H gel occurs with increasing hydration, especially at a hydration level in which a monolayer of water around the basic units of cement materials is predicted by different structural models. Below this hydration level both processes 2 and 3 have an Arrhenius temperature dependence. However, at higher hydration level, a non-Arrhenius behavior temperature dependence for process 3 over the whole accessible temperature range and, a crossover from low-temperature Arrhenius to high-temperature non-Arrhenius behavior for process 2 are observed. Characteristics of these processes will be discussed in this work.
采用宽频介电谱（BDS；10(-2)-10(6) Hz）在低温范围（110-250 K）下研究了水动力学在水化硅酸钙水合物（C-S-H）凝胶中的受限行为。探索了 C-S-H 凝胶中的不同含水量（6-15wt%），所有研究温度下的水都保持无定形。通过 BDS 发现了三个弛豫过程（从最快到最慢标记为 1 到 3），其中两个是首次报道。我们表明，随着水化程度的增加，C-S-H 凝胶的介电弛豫发生了强烈变化，特别是在不同结构模型预测的水泥材料基本单元周围的单层水的水化水平。在此水化水平以下，过程 2 和 3 均具有 Arrhenius 温度依赖性。然而，在较高的水化水平下，过程 3 在整个可及温度范围内呈现出非 Arrhenius 温度依赖性行为，过程 2 从低温 Arrhenius 到高温非 Arrhenius 行为的转变。本文将讨论这些过程的特征。
