Immittance spectra for Portland cement/fly ash-based binders during early hydration

Journal Article · Mon Mar 01 04:00:00 EST 1999 · Cement and Concrete Research

DOI:https://doi.org/10.1016/S0008-8846(98)00209-9· OSTI ID:351539

McCarter, W J; Starrs, G; Chrisp, T M ^[1]

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1. Heriot-Watt Univ., Edinburgh (United Kingdom). Dept. of Civil and Offshore Engineering

A range of immittance formalisms is exploited to understand the nature of conduction and polarization within Portland cement-based binders over the frequency range 1 Hz to 1 MHz. Data are presented for binders with and without aggregate additions; of particular interest was the electrical response of a binary combination of ordinary Portland cement and fly ash. Regarding the latter, when presented on a Nyquist diagram, a characteristic plateau region emerged between the electrode spur and the bulk arc. When presented in the form of dielectric constant and conductivity as a function of frequency, a region of dispersion was evident for all systems. Furthermore, it was shown that by undertaking a dielectric frequency-domain analysis of the data, the experimental results could be synthesized across the frequency range 1 kHz to 1 MHz. Rather than ascribing separate processes to each impedance zone, the observed response could be attributed to a single bulk polarization process. When transformed into the complex impedance plane, there was also good agreement between synthesized and measured response. It is postulated that polarization is as a result of double-layer effects on the grain with a relaxation frequency in the low kilohertz region.

• OSTI ID: 351539
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Journal Issue: 3 Vol. 29; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
36 MATERIALS SCIENCE
CONCRETES
ELECTRICAL PROPERTIES
FLY ASH
FREQUENCY DEPENDENCE
HYDRATION
PORTLAND CEMENT
WASTE PRODUCT UTILIZATION