Influence of Binder Type on the Chloride Threshold Level for Steel Corrosion in Concrete

Abstract

The present study concerns the influence of binder type on the chloride-induced corrosion being accompanied by the chloride threshold level (CTL), chloride transport and as their results the corrosion-free life. Two levels of cement content, 30% PFA and 65% GGBS concrete were employed. It was found that the most dominant factor to the CTL is the entrapped air void content at the steel-concrete interface, irrespective of the chloride binding capacity, binder type and acid neutralisation capacity of cement matrix. The CTL for lower interfacial air void contents was significantly increased up to 1.52% by weight of cement, whereas a same mix produced 0.35% for a higher level of voids. Because of a remarkable reduction in the diffusion for GGBS concrete, its time to corrosion ranges from 255 to 1,250 days, while the corrosion-free life for control varies from 20 to 199 days sand for 30% PFA concrete from 200 to 331 days.