Experimental procedure for the calculation of chloride diffusion coefficients in concrete from migration tests

Abstract

A decrease in the time required for testing the resistance of concrete to chloride penetration is proposed, based on the so-called rapid chloride permeability test developed by Whiting. Numerous papers have been published presenting results obtained by this method, which has already been standardized by AASHTO, although its interpretation is disputed. A previous paper presented a theoretical basis to improve the Whiting set-up and to convert it into a reliable method for the calculation of chloride diffusion coefficients. The approach was based on the fundamentals of electrochemistry regarding transport in electrolytes, by use of the Nemst—Planck and Nemst—Einstein equations. In this Paper preliminary experimental results are presented and natural diffusion and migration tests are compared. The results indicate a satisfactory agreement of the two test types and the soundness of the simplifying assumptions adopted. The experimental procedure and possible improvements are described.