介电谱
材料科学
互连性
多孔性
电导率
微观结构
电介质
热扩散率
复合材料
矿物学
离子电导率
热力学
化学
电极
电解质
物理化学
电化学
物理
光电子学
人工智能
计算机科学
作者
B. J. Christensen,R. Tate Coverdale,Rudolph Olson,Steven Ford,Edward J. Garboczi,Hamlin M. Jennings,Thomas O. Mason
标识
DOI:10.1111/j.1151-2916.1994.tb04507.x
摘要
This work concerns the state of the art for use of impedance spectroscopy for studying the evolving microstructure of cement‐based materials during hydration. Features of the spectra are discussed and related to components of the microstructure with the assistance of pixel‐based computer modeling techniques. It is proposed that the enormously high relative dielectric constants (∼10 5 ) observed just after set are the result of dielectric amplification and are related to the distribution of pore sizes and the thickness of product C─S─H layers separating the pores. The conductivity is related to the volume fraction of porosity, the conductivity of the pore solution, and the interconnectivity of the porosity. The conductivity, when normalized by that of the pore solution, i.e., inverse formation factor, is a measure of this interconnectivity and can be used to predict such engineering properties as ionic diffusivity and water permeability. Composite mixing laws are employed to aid in explaining the behavior of the conductivity and to obtain a qualitative measure of the pore shape with hydration. Procedures for predicting the conductivity of the pore solution and for subtracting out electrode lead effects at high frequency are discussed.
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