Ettringite Induced Heaving and Shrinking in Kaolinite Clay

Various field studies have revealed that sulfate induced heaving is caused by the formation of ettringite due to cement and lime treatments of sulfate rich clay. Variations in swell and shrink properties can lead to premature pavement failures, which can result in higher maintenance costs. This paper presents experimental results obtained from Kaolinite clay treated with different sulfate amounts and stabilized with cement and lime. Several laboratory experiments including swell, shrinkage, strength properties of these clays were conducted. It was observed that ettringite mineral formed in both lime and cement treated sulfate clays. Overall, lime treated Kaolinite clay experienced lesser swell strains and swell pressures and higher volumetric shrinkage than the cement treated Kaolinite clay due to variations in moisture and density conditions of the respective treated clays.