ABSTRACT
The ability of the concrete to resist chloride ion penetration is one of the most essential properties in determining the service life of concrete structures. A number of long-term and accelerated methods to test concrete for chloride penetrability have been developed. The long-term methods are based on prolonged exposure of concrete samples to chlorides followed by profiling of chloride content after a specified time of exposure. These methods are very accurate in research projects but they are time consuming and in construction quality control demands the results may be too late for remedial measures. Transport of chlorides in the 90-day ponding test (AASHTO T259-80) is due to a combination of absorption, diffusion and wicking. Pure diffusion of chloride ions is assumed
in the Nordtest NT Build 443-95 and in the ASTM C1556-03 and the diffusion coefficient is determined by fitting the solution equation of Fick’s Second Law to the measured chloride ion contents in non-linear regression analysis.
