Reliability of chloride testing results in cementitious systems containing admixed chlorides

Abstract

ABSTRACT Chloride concentrations are often evaluated for concrete mixtures used in new construction for quantity control purposes. This paper reports on the reliability of results from ASTM C1152 (acid-soluble) and ASTM C1218 (water-soluble) tests commonly adopted for measuring chlorides in concrete. The effects of cementitious material type, water-binder ratio, admixed chloride level, and degree of carbonation on chloride concentrations of cementitious systems are evaluated. Results show that the release of bound chlorides due to carbonation could be represented by an increase in ASTM C1218 test value. Chloride concentrations measured using ASTM C1152 testing could be significantly lower than the actual chloride concentration for carbonated systems. This underestimation, as a percent of total chloride concentration, could be as high as 40% depending on the cementitious material type and chloride admixed level. Preliminary results indicate that ASTM C1218 could be more reliable when compared to ASTM C1152 for systems with admixed chlorides.