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Analysis of the Impedance Spectra of Short Conductive Fiber-Reinforced Composites



J M. Torrents, T Mason, A Peled, S Shah, Edward Garboczi


The presence of small amounts of short conductive fibers in a composite of finite matrix conductivity results in the subdivision of the one matrix impedance arc into two separate low and high frequency arcs in the complex impedance plane. These features are attritutable to a frequency-switchable interfacial impedance on the fiber surfaces, rendering them insulating at DC and low AC frequencies, but conducting at intermediate frequencies. A combination of physical simulations (single wires in tap water) and pixel-based computer modeling was employed to investigate the roles of fiber pull-out, debonding, and orientation on the impedance response of fiber-reinforced composites. The ratio of the low frequency arc size to the overall DC resistance (γ-parrameter) is sensitive to pull-out and/or debonding, especially when a fiber just barely makes contact with the matrix. The γ-parameter is also quite sensitive to fiber orientation with respect to the direction of the applied field. Ramifications for the characterization of cement, ceramic, and polymer matrix composites are discussed.
Journal of Materials Science
No. 16


cement, composites, fibers, impedance, orientation, spectroscopy, spreading resistance


Torrents, J. , Mason, T. , Peled, A. , Shah, S. and Garboczi, E. (2001), Analysis of the Impedance Spectra of Short Conductive Fiber-Reinforced Composites, Journal of Materials Science, [online], (Accessed October 2, 2023)
Created July 31, 2001, Updated October 12, 2021