Factors influencing chloride test results of cementitious systems

Many committees from the American Concrete Institute (ACI) report allowable admixed chloride (C_A) limits for fresh concrete to minimize the risk of corrosion of steel reinforcement. These limits are based on water-soluble and acid-soluble chloride test methods. While most ACI documents report water-soluble C_A limits only, some report both acid- and water-soluble C_A limits by assuming water- to acid-soluble chloride ratio between 0.75 and 0.8. Debate exists within the concrete industry on adopting a single test method to assess admixed chlorides. Test results from this research indicate that the ratio of water- to acid-soluble test results vary for different cementitious systems, with mean values ranging from 0.08 to 0.77, indicating that the assumed 0.75 to 0.8 range is incorrect. The effects of study parameters on the outcome of the test results are discussed. Based on the generated test data, recommendations are provided for possible future revisions to ACI C_A limits.