Gas diffusion in cement pastes: An analysis using a fluctuating diffusivity model
Gas diffusion in cement pastes: An analysis using a fluctuating diffusivity model
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DOI：
10.1016/j.conbuildmat.2023.133411
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发表时间：
2023-01
影响因子：
7.4
通讯作者：
Fumiaki Nakai;Takato Ishida
中科院分区：
文献类型：
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作者：
Fumiaki Nakai;Takato Ishida
本研究提出应用波动扩散率（FD）的概念，气体分子在胶凝材料中的扩散，主要是通过一个双态波动扩散率（2SFD）模型。采用2SFD模型研究了氧在水泥浆体中的扩散。这种分析提供了一个合理的描述水泥浆体中的氧扩散系数，并建议存在的非高斯扩散，这是由于非均匀的微观结构。分子位移的概率密度中存在非高斯性，其特征在于比高斯分布的尾部更重，可能会显着影响混凝土结构的耐久性。
This study proposes applying the concept of fluctuating diffusivity (FD) to the diffusion of gas molecules in cementitious materials, mainly through a two-state fluctuating diffusivity (2SFD) model. The 2SFD model was utilized to investigate oxygen diffusion in cement pastes. This analysis provides a reasonable description of the oxygen diffusion coefficient in cement pastes and suggests the presence of non-Gaussian diffusion, which is attributed to the heterogeneous microstructure. The presence of non-Gaussianity in the probability density of the displacement of the molecule, characterized by heavier tails than those of the Gaussian distribution, may significantly impact the durability of concrete structures.