Abstract
The impedance response of conductive fiber-reinforced cement-based materials was investigated using model systems (physical simulations) consisting of conducting needles in aqueous solutions. Two discrete bulk arcs are observed in the Nyquist plots for fiber-reinforced samples, while only a single bulk arc was observed for samples without fibers. This difference is attributable to thin, resistive, and highly capacitive layers (e.g., oxide film or polarization/double layers) which reside on the surfaces of the conducting fibers. These layers fully insulate the fibers at low frequencies (near DC), so that the highly conducting fibers behave as if they were insulating fibers. At intermediate frequencies, these layers short out, so that the fibers act as highly conducting elements in the microstructure. Spreading resistance effects from the ends of the fibers play an important role in the high frequency behavior. Pixel-based computer modeling results are presented to rationalize both DC and high frequency behavior. Experimental and modeling results are used to develop an equivalent circuit model containing a frequency-switchable fiber coating element.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 585-592 |
| Number of pages | 8 |
| Journal | Cement and Concrete Research |
| Volume | 30 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 2000 |
Funding
This work was supported by the National Science Foundation Science and Technology Center for Advanced Cement-Based Materials under grant no. CHE-91-20002. JMT acknowledges the support of the Spanish Government through the Secretary of the State for Universities, Research and Development of the Ministry of Education and Culture under grant no. PR98-0036975531.
ASJC Scopus subject areas
- Building and Construction
- General Materials Science