ABSTRACT
Three types of rapid chloride test methods have been developed so far. In all of them, a concrete specimen is placed adjacent to a chloride solution on the one side, and a chloride-free solution on the other. The first type of method is represented by the AASHTO T277 (1983), developed by Whiting et al (1981), in which the total charge passed through a specimen during a six hour period under a 60 V. Then the potential difference is measured and the value used as a chloride permeability index. In the second method which is developed by Dhir et al (1990), the steady state chloride flux is measured under a 10 V potential difference empirically to the chloride diffusion D of the concrete. In the last method which is represented by Tang & Nilsson (1992), the depth of chloride penetration under a 30 V potential after 8 hours is measured and fundamental electrochemical theory is used to calculate D. There is a need for a chloride penetration test that is theoretically sound and also is as more rapid as the AASHTO method. Based on electrochemical theory, a very rapid chloride conduction test has been developed at the University of Cape Town (Feldman et al 1994). The authors present a new test method combining Cape Town method and RCPT method that has no disadvantages of traditional method. This paper deals with the electrochemical principles that led to the development of the new test method for chloride penetration. It is also described the test method as well as the procedure used to determine diffusivity from conductivity measurements.
