DOI

10.5703/1288284314646

Abstract

Many agencies are interested in using a rapid test method for measuring the electrical properties of concrete (i.e., the resistivity or conductivity) since the electrical properties can be related to fluid transport (e.g., ion diffusion). The advantage of electrical testing is that it is relatively easy to perform and the test method is relatively fast (less than a minute). Over the last century, many studies have investigated different approaches for measuring electrical properties. This paper describes the variability associated with measuring the bulk resistivity along the longitudinal axis of a cylinder after placing electrodes on either end. A multi-laboratory evaluation was performed using ten laboratories. Data from this evaluation provided variability data for twelve concrete mixtures at testing ages of 28, 56, and 91 days. Information on the variability is important in the development of precision and bias statements for standard test methods. In addition, this work discusses how the resistivity results obtained from this test can be correlated with surface resistivity measurements made using the Wenner probe. A linear agreement was noticed between the Wenner test and the measurement through the cylinder, but with a factor confirmed by previous research by Morris et al. (1996). Additionally, the effect of electrode resistance was discussed and for high resistivity concrete such as that used in much of the transportation infrastructure, this effect appears to be negligible; however, it can be accounted for easily.

Report Number

FHWA/IN/JTRP-2011/21

Keywords

concrete, resistivity, surface resistivity, bulk resistivity, RCPT, electrical properties, electrode resistance, variability, precision statements, standard development, inter-laboratory test, Round-robin test, SPR-3509

SPR Number

3509

Performing Organization

Joint Transportation Research Program

Publisher Place

West Lafayette, Indiana

Date of this Version

2011