Impedance spectroscopy of fiber-reinforced cement composites

Thomas O Mason, M. A. Campo, A. D. Hixson, L. Y. Woo

Research output: Contribution to journalArticle

63 Citations (Scopus)

Abstract

The addition of chopped conductive fibers to cement matrices results in a characteristic "dual-arc" electrical impedance spectrum below the percolation threshold. This behavior can be explained on the basis of a "frequency-switchable fiber coating" model, in which a "coating" (e.g., passive oxide film on steel or charge transfer resistance/double layer on other conductors) insulates the fibers at DC and low AC frequencies, but is shorted out at higher frequencies, where the fibers become short-circuit paths in the composite microstructure. The present work investigates various factors governing the impedance spectra of fiber-reinforced cement composites - fiber aspect ratio, fiber volume fraction, fiber orientation (relative to field direction), and fiber shape. The "gamma" factor (ratio of the low frequency arc diameter to DC resistance) is a useful parameter to characterize the microstructure-property relationships of fiber-reinforced composites.

Original languageEnglish
Pages (from-to)457-465
Number of pages9
JournalCement and Concrete Composites
Volume24
Issue number5
DOIs
Publication statusPublished - Oct 2002

Keywords

  • Carbon fiber composites
  • Electrical impedance spectroscopy
  • Steel fiber composites

ASJC Scopus subject areas

  • Industrial and Manufacturing Engineering
  • Ceramics and Composites

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