Relation between colourimetric chloride penetration depth and charge passed in migration tests of the type of standard ASTM C1202-91

Abstract

The great interest in the knowledge of the amount of chlorides that have penetrated into concrete is due to the fact that corrosion of reinforcement in concrete initiates when chloride content in contact with rebars exceeds a threshold value. So, a number of methods to measure the diffusion coefficient of Cl− in concrete have been developed; one of them, from the use of a colourimetric method, derived from its ease in practice. Some questions have been raised about this method, concerning the amount of chlorides at which the colour change takes place. In this article, comparison between total chloride profiles in migration experiments of the AASHTO type (ASTM C1202-91), and results from colourimetric test, as well as a relationship between colourimetric penetration depth and charge passed, are given.