Mechanisms involved in the accelerated test of chloride permeability

This paper describes a specific device that allows good assessment of the mechanisms involved in the standardized test of the accelerated determination of chloride permeability. Current, pH, conductivity, and chloride concentration were regularly monitored during the test. It appears that electrolysis is the main process involved in this test and that the role of hydroxide ions is essential. We underlined the analytical precautions of chloride determination in the anodic compartment. The AASHTO test detects correctly the interconnected pores network in which ions migrate, but it does not determine the true importance of the chloride ions that flow through the material. Consequently, if concrete samples of different compositions are to be compared, a simple determination of the amount of electrical charges could lead to serious misinterpretation. (C) 1999 Elsevier Science Ltd. All rights reserved.