Engineering and durability properties of fly ash treated lime-stabilised sulphate-bearing soils

Michael J. McCarthy (Lead / Corresponding author), Lazlo J. Csetenyi, Anisha Sachdeva, Ravindra K. Dhir

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)


The paper describes a study carried out to investigate the engineering and durability properties of lime-stabilised soils treated with low-lime fly ash to limit swelling (heave) due to sulphate, associated with the ground improvement process. Two clays (Lias and Oxford with total potential sulphate levels >. 1.0%), a quicklime, two fly ashes (fine/low loss-on-ignition (LOI)/dry; and coarse/high LOI/wet (pond) stored) and a ground granulated blastfurnace slag (GGBS) were considered. The lime-stabilised soils contained 3% quicklime and various levels of fly ash (up to 24%) and GGBS (up to 9%), and were tested at optimum moisture content and maximum dry density. The properties considered included, immediate-bearing index, unconfined compressive strength, indirect tensile strength, water permeability and frost-heave. The results indicate that for most of these, the fly ash combinations gave improvements compared to lime-only treated soils, with the benefits generally increasing with addition level. Between fly ashes, the fine/dry material mainly gave better properties for those considered. This differs from behaviour noted previously for sulphate-heave, where coarser/wet-stored fly ash was most effective in minimizing the process. At comparable application levels, GGBS contributed more than fly ash to the properties of the lime-stabilised soils. The underlying mechanisms associated with these effects and the practical implications of the study are explored.
Original languageEnglish
Pages (from-to)139-148
Number of pages10
JournalEngineering Geology
Early online date14 Mar 2014
Publication statusPublished - 23 May 2014


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