Carbonation-induced reinforcement corrosion in silica fume concrete

This study presents the results of carbonation depth and carbonation-induced reinforcement corrosion in concrete samples with silica fume additions of up to 20% and water/binder ratios ranging from 0.30 to 0.80. The behavior of the additions is determined by the w/b ratios. For w/b ratios lower or equal to 0.45–0.50, carbonation processes in these materials are controlled by the porosity of the material and the consumption of Ca(OH)2 has a negligible effect on carbonation. For higher w/b ratios, the consumption of Ca(OH)2 plays a significant role. At the same time, the results of reinforcement corrosion indicate that the effect of silica fume additions depends on their concentration. In concentrations equal to or lower than 10%, silica fume will not reduce corrosion resistance and it may actually increase it when used in concentrations below this level. When used in concentrations greater than 10%, silica fume increases the potential for carbonation-induced reinforcement corrosion.