Experimental and numerical investigations on macrocell corrosion of partially carbonated reinforced concrete with supplementary cementitious materials

The use of supplementary cementitious materials (SCMs) has led to a decrease in the corrosion initiation of carbonated reinforced concrete (RC). Hence, studies on the corrosion propagation of carbonated SCM concrete are becoming important but remain limited. In this study, ordinary Portland cement (OPC) was partially replaced with pulverized fly ash (PFA), ground granulated blast-furnace slag and silica fume, using two replacement levels. Experiments were conducted to investigate the microcell and macrocell corrosion behaviors of carbonated SCM concrete under wetting and drying cycles. A novel numerical model is proposed and validated to examine the effect of macrocell corrosion on the duration of corrosion propagation. Results show that macrocell corrosion plays a more important role in carbonated SCM concrete compared with OPC concrete. The corrosion of carbonated PFA concrete can be accelerated by 170% upon galvanic coupling, resulting in a decrease of 47% in the duration of the corrosion propagation.