Permittivity of Portland cement concrete at low RF frequencies

Journal Article · Fri Apr 01 00:00:00 EST 1994 · Materials Evaluation; (United States)

OSTI ID:7301086

Su, W; Hazim, O A; Al-Qadi, I L; Riad, S M ^[1]; Al-Qadi, I L ^[2]

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1. Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Bradley Dept. of Electrical Engineering
2. Virginia Polytechnic Inst. and State Univ., Blacksburg, VA (United States). Via Dept. of Civil Engineering

Portland cement concrete (PCC) specimens were cast and most cured for 28 days. Their complex permittivity was measure dover a frequency ranger of 100 kHz--40 MHz as part of an ongoing study intended to develop a database of electromagnetic properties of PCC. Such information would allow the improvement of current nondestructive evaluation (NDE) methods used to evaluate concrete structures. Low RF (radio frequency) measurements were carried out using a parallel plate capacitor setup connected to an HP 4195A Network/Spectrum Analyzer, Using a complex capacitance model for the capacitor, the complex permittivity of twelve different PCC mixes was evaluated; measurements were performed on four specimens per batch. The selected mixes included three water-to-cement (w/c) ratios, two aggregate types, and two levels of entrained air content; Type 1 portland cement was used. Preliminary measurements showed that the dielectric constant of the concrete specimens varied over frequency from nearly 150 at 1 MHz to around 6 at 40 MHz after 28 days of moist curing. Measured loss tangent was in the range of 0.86--1.8 at 1 MHz and 1.0--2.9 at 40 MHz. A significant effect of w/c ratio, type of aggregate, air entrainment, and the curing state of specimens was observed.

• OSTI ID: 7301086
• Journal Information: Materials Evaluation; (United States), Vol. 52:4; ISSN 0025-5327
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
36 MATERIALS SCIENCE
CONCRETES
ELECTROMAGNETIC TESTING
PERMITTIVITY
PORTLAND CEMENT
DIELECTRIC PROPERTIES
EXPERIMENTAL DATA
BUILDING MATERIALS
CEMENTS
DATA
ELECTRICAL PROPERTIES
INFORMATION
MATERIALS
MATERIALS TESTING
NONDESTRUCTIVE TESTING
NUMERICAL DATA
PHYSICAL PROPERTIES
TESTING
420500* - Engineering- Materials Testing
360606 - Other Materials- Physical Properties- (1992-)