Performance evaluation of rapid chloride permeability test in concretes with supplementary cementitious materials

Rapid chloride permeability test (RCPT) is one of the widely used test methods to rapidly assess the durability of concrete, specifically its resistance against chloride ion penetrability. Many researchers have questioned the applicability of RCPT in mixes having supplementary cementitious materials (SCMs). The present work analyses the performance of RCPT in concretes that contain different dosages of three SCMs such as slag, Class F fly ash and Class C fly ash. In addition to the conventional measurements of current at half an hour interval, other details of the tests such as initial current, temperature development during the experiment, and depth of chloride ion penetration are also measured. Good correlations are obtained between total charge passed and other additional measurements such as initial current, depth of chloride ion penetration, temperature reached during the experiment etc., which are reported by other researchers with mixes having only OPC as binder. Furthermore, the results of RCPT are well correlated with the results of Wenner 4-probe surface resistivity test, which is free from many of the criticisms of RCPT. The paper concludes that RCPT can be used as a reliable accelerated test method to assess chloride ion penetrability in concretes that have supplementary cementitious materials such as fly ash and slag.