Chemical profiles of cement pastes exposed to a chloride solution spray

This paper reports on the findings of a study of the chemistry of chloride penetration into cement pastes. Three binder combinations were used with th ree types of curing. At certain exposure times, specimens were sliced at 5- mm intervals, ground, and analysed using X-ray fluorescence (XRF) and therm ogravimetry (TG) techniques. Up to B-month exposure results are reported in this paper. As a result of leaching of calcium, silicon content was used t o determine binder content for the XRF measurements. It was found that the vast majority of chloride permeation had occurred by absorption, and that c uring by sealing in film or the addition of self-cure admixture more than h alved the depth to which chlorides penetrated. In some instances, sodium wa s present in proportionally higher quantities than chloride, which has been attributed to the replacement of sodium ions by potassium ions. (C) 1999 E lsevier Science Ltd. All rights reserved.