Corrosion Resistance of Recycled Aggregate Concrete Incorporating Slag

The main objective of this paper is the investigation of the corrosion resistance of reinforced concrete containing various proportions of recycled aggregates (RA) combined with 25% ground-granulated blast-furnace slag (GGBS) as a partial cement replacement. An accelerated corrosion system was designed to test the steel corrosion in reinforced concrete by subjecting the samples to 150 and 300 wetting-and-drying cycles. The results, in general, showed that the use of RA in concrete mixtures was found to reduce the compressive strength, increase chloride penetration, decrease the corrosion potential of reinforcing bars, reduce the electrical resistance of concrete, and hence increase the corrosion risk. However, better results were achieved by the addition of 25% GGBS, which increased the core compressive strength and electrical resistance. Moreover, better results were achieved for normal and slag mixtures that have 0.788 in. (20 mm) concrete cover than those having 0.394 in. (10 mm) cover.