Using Impedance Spectroscopy to Assess the Viability of the Rapid Chloride Test for Determining Concrete Conductivity
Kenneth A. Snyder, Chiara C. Ferraris, Nicos Martys, Edward Garboczi
The suitability of using the initial current from the rapid chloride test (ASTM C 1202) to determine specimen conductivity is tested using impedance spectroscopy with a frequency spectrum of 10 Hz to 1 MHz. The specimen conductivity has an analytical relationship to specimen diffusivity and so is a useful quantity in service life prediction. Measurements made on specimens of different lengths indicate that the total charge passed during the six hour conduction test carried out according to ASTM C 1202, however, is not a direct measure of specimen conductivity. Further, ohmic heating during the six hour test makes it nearly impossible to directly measure any specimen transport property from the results. The total charge passed during the six hour conduction test is, therefore, not a reliable quantity for service life prediction. Impedance spectroscopy results indicate that corrosion may form on the brass electrodes, thereby adding bias to the conductivity estimate.Results indicate that a direct current (DC) measurement of resistance using a potential of 60 volts is sufficient to overwhelm polarization effects, thereby yielding an accurate estimate of the true specimen conductivity.
, Ferraris, C.
, Martys, N.
and Garboczi, E.
Using Impedance Spectroscopy to Assess the Viability of the Rapid Chloride Test for Determining Concrete Conductivity, Journal of Research (NIST JRES), National Institute of Standards and Technology, Gaithersburg, MD
(Accessed March 2, 2024)