Sulfate resistance and carbonation of plain and blended cements

Results of an experimental investigation on the sulfate resistance and carbonation of plain and blended cement mortars are reported in this paper. In the sulfate resistance test all the specimens were immersed in a 5% Na2SO4 solution for 24 months. Two different types of lignite fly ashes and two natural pozzolans were used for the production of 13 blended cements. An ordinary portland cement and a commercially available blended cement were also used for reference. The effect of mineral admixtures on the carbonation depth of mortars was also investigated. Results show that the addition of pozzolanic admixtures in most cases had a positive effect on the sulfate resistance. The carbonation depth in all blended mortars was greater than that in portland cement mortar. However the rate of carbonation of blended mortars was reduced as hydration progressed.