A study on chloride ion penetration in concrete from salt ponding and other accelerated tests

Abstract

The salt ponding test (SPT) is widely used to evaluate the chloride ion penetration resistance of concrete in cement based materials. However, SPT is considered to be time consuming, since the duration of test is more than 90 days. This paper provides a brief review on some of the accelerated test procedures available for measuring chloride ion transport in concrete. In the present study, OPC (ordinary portland cement) concrete with three water-to-cement ratios (w/c) viz., 0.55, 0.45, and 0.35 are used. 90-day SPT, Rapid chloride permeability test (RCPT), Colourimetric technique, Rapid chloride migration test (RCMT) and Accelerated chloride migration test (ACMT) are carried out on standard concrete samples. Some studies are also conducted on specimens of portland pozzolana cement (PPC) concrete. Though the 28-day compressive strengths are relatively less (9 to 12.5%), the chloride ion penetration depths obtained from colourimetric technique is lower for PPC concretes compared to that the corresponding OPC concretes. RCMT results show that the migration coefficients of PPC concretes are nearly one-half to that of the corresponding OPC concretes. This indicates that the PPC concretes are more resistant to chloride ion ingress than that of corresponding OPC concretes. The diffusion coefficient obtained from chloride profile content and colourimetric method is closely matching and hence, colourimetric technique can be used for ponding test diffusion coefficient estimation.