Effect of ground granulated blast-furnace slag (GGBFS) and silica fume (SF) on chloride migration through concrete subjected to repeated loading

The effect of ground granulated blast-furnace slag (GGBFS) and silica fume (SF) on the chloride migration through concrete subjected to repeated loading was examined. Portland cement was replaced by 20%, 30%, 40% GGBFS and 5%, 10% SF, respectively. Five times repeated loadings were applied to specimens, the maximum loadings were 40% and 80% of the axial cylinder compressive strength (f′_c), respectively. Chloride migration through concretes was evaluated using the rapid chloride migration test and the chloride concentration in the anode chamber was measured. The results indicate that the transport number of chloride through concrete containing 20% and 30% GGBFS replacements and 5% and 10% SF replacements is lower than that of the control concrete, but 40% GGBFS replacement increases the transport number of chloride. Five loadings at 40% f′_c or 80% f′_c increase the transport number of chloride for all mixes investigated in this study. 5% SF replacement has a very close effect on the chloride permeability of concrete with 20% GGBFS when concrete is subjected to 40% f′_c or 80% f′_c.