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 language | English |
|---|---|
| Pages (from-to) | 457-465 |
| Number of pages | 9 |
| Journal | Cement and Concrete Composites |
| Volume | 24 |
| Issue number | 5 |
| DOIs | |
| Publication status | Published - Oct 2002 |
Keywords
- Carbon fiber composites
- Electrical impedance spectroscopy
- Steel fiber composites
ASJC Scopus subject areas
- Industrial and Manufacturing Engineering
- Ceramics and Composites