Michael J McCarthy, Laszlo J Csetenyi, Anisha Sachdeva, Ravindra K Dhir, Division of Civil Engineering, University of Dundee. This paper was first published in GE’s January 2011 issue.
Lime stabilisation is an effective method of transforming nonconforming clay soils so that they are suitable for construction. In general, quicklime is spread over the application area, rotavated in to the required depth, and then allowed to mellow prior to compaction.
The processes occurring between lime and clay minerals in the soil, in the presence of moisture, lead to several effects, including reduced plasticity, improved workability and enhanced engineering properties of the treated material. Further benefits can be achieved with the addition of fly ash or ground granulated blastfurnace slag (GGBS) by repeat-spreading and rotavating before compaction (two stage operation). Stabilisation methods, in avoiding the need for soil replacement, also offer several environmental and economic advantages.