Use of Electrolytic Resistivity and the Measurement of Charge as Test Methods for Chloride Resistance of Concrete-Correlations with the Rapid Chloride Migration Test

To determine the resistance of a concrete against chloride penetration, the so-called Rapid Chloride Migration (RCM) Test is often used in Europe, for which different test specifications with different boundary conditions exist. In addition, alternative methods are being considered: firstly, a Modified Chloride Migration (MCM) test, in which the charge flow through the test specimen is utilised, and secondly, the use of the electrolytic resistivity of the concrete. In both cases, the migration coefficient is determined via a regression function. Compared to the current standard RCM test, the charge measurement method and the use of the electrolytic resistivity offers the advantage of a significantly shorter test duration and less testing effort. However, the available data on the correlation between the individual methods still needs to be further developed, particularly with regard to different boundary conditions in the RCM test due to different test specifications. In the investigations presented here, conventional RCM tests with different compositions of the catholyte solution were used for concretes and mortars and additional measurements were added to determine the charge flow and the electrolytic resistivity. The results so far indicate that existing correlations between the individual test methods must be formulated depending on certain test boundary conditions.