Influence of ground granulated blastfurnace slag on the sulphate resistance of lime-stabilized kaolinite

This paper describes the influence of ground granulated blastfurnace slag (GGBS) on the durability of lime-stabilized kaolinite in 4·2% Na₂SO₄ solution. Sulphate durability was assessed in the laboratory by means of linear expansions measurements, microstructure and mineral phase analysis of compacted cylinders of the lime-stabilized kaolinite with different percentages of lime replacement by GGBS. The cylinders were immersed in 4·2% Na₂SO₄ solution and also in deionized water for various time periods. The exposure test data showed that the effect of GGBS on reducing expansion in 4·2% Na₂SO₄ solution is dramatic. The results also showed that high percentages of replacement of lime with slag (in particular 83%), with just enough lime to activate the slag, were the most effective in preventing sulphate solution attack.