Effect of silica fume on durability of concrete composites containing fly ash

In this paper, the effect of silica fume on the workability and durability of concrete composites containing fly ash, including water impermeability, dry shrinkage property, carbonation resistance and freeze-thaw resistance, are presented. Four different silica fume contents (3%, 6%, 9% and 12%) were used. The results indicate that the addition of silica fume has greatly improved the durability of water impermeability, the carbonation resistance and the freeze-thaw resistance of the concrete composites containing fly ash. With the increase in silica fume content, the length of water permeability and the carbonation depth of the specimens decrease gradually, and the relative dynamic elastic modulus of the specimens has a tendency to increase. However, the addition of silica fume has a little adverse effect on the workability and dry shrinkage property of concrete composites containing fly ash. With the increase in silica fume content, both the slump and the slump flow decrease gradually, and the dry shrinkage strain increases gradually