### Experimental Investigation on the Strength and Durability ...

This is true for 3-days, 7- days, 28-days, and 60-days compressive strength. The strength activity index for 3-days, 7-days, 28-days, and 60-days for 16% of silica fume is 1.65, 1.33, 1.49 and 1.41 respectively. The effect of silica fume content on the Compressive strength of concretes is shown in Figure 2. Resistance Against Acid Attack