Al-Qadi, I. L., W. Su, S. M. Riad, R. Mostafa, and O. Hazim. 1994.
Coaxial Fixture Development to Characterize Portland Cement Concrete.

Proceedings of the Symposium on Time Domain Reflectometry in Environmental, Infrastructure, and Mining Applications, Evanston, Illinois, Sept 7-9, U.S. Bureau of Mines, Special Publication SP 19-94, NTIS PB95-105789, pp. 443-452
(posted June 27, 1996)

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Electrical characterization of portland cement concrete (PCC) is necessary for reliable operation of many electromagnetic nondestructive evaluation (NDE) techniques. Examples of such techniques include ground penetration radar (GPR). To better understand the dielectric properties of PCC, a study was planned to evaluate PCC complex permittivity and magnetic permeability over a wideband of frequencies (1 Mhz to 10 Ghz) using both time domain and frequency domain measurement techniques. In this paper, the design of a coaxial fixture measuring in the frequency range of 50 Mhz to 1 Ghz is presented. The fixture was designed to allow the evaluation of large PCC specimens and obtain an average effect of PCC components. A time domain reflectometry (TDR) setup was used in the design of the fixture and to test its electrical performance. Thru, Reflection, and Line (TRL) calibration standards were used and a two-port S-parameter model was used to compute the complex permittivity and magnetic permeability. Results are presented which demonstrate the feasibility of this fixture for characterizing electrical properties of PCC.