Effect of silica fume or granulated slag on sulphate attack of ordinary portland and alumina cement blend

The effect of silica fume or granulated slag as high alumina cement (HAC) substitutes, on sulphate attack of ordinary Portland and alumina cement blend up to complete substitution and up to 12 months, was studied. The results indicate that the cement pastes with silica fume give higher combined water and lower free lime contents than those containing granulated slag. The increase of HAC substitution by silica fume or granulated slag in the OPC–HAC blend decreases the aggressive attack of sulphate ions on the hardened cement pastes, yet the granulated slag is more effective than the silica fume.