Comparison of Two Methods to Assess the Resistance of Concrete to Chloride Ion Penetration

The industry standard currently accepted method for assessing the resistance of concrete to penetration of chloride ions is commonly known as the rapid chloride permeability (RCP) test. The test is time-consuming and laborious and the user must be extremely careful to ensure accuracy, making it problematic for inclusion as a performance variable in a concrete specification. A potential alternative to the RCP test is the surface resistivity (SR) test, a method that is dramatically easier, faster, and requires far less special care than the RCP test. The research reported herein was directed toward determining a correlation between RCP and SR test measurements for Tennessee bridge deck concrete (based on cylinders collected from concrete bridge decks being constructed across the state) and evaluating the appropriateness of the SR test as an alternative to the RCP test for inclusion in a specification for bridge deck concrete. Results of the testing showed a clear correlation between the two methods and identified potential limits for possible inclusion as a performance requirement in a specification.