Article ID Journal Published Year Pages File Type
4743481 Engineering Geology 2014 10 Pages PDF
Abstract

•Practical properties of lime-stabilised clays containing sulphate are considered.•Two clays, two fly ashes (fine and coarse) and a quicklime were investigated.•Compared to lime-only treated clay, properties mainly improved with fly ash addition.•Unlike for sulphate-heave, fine fly ash gave better performance than coarse material.•Given the behaviour observed, a suggested approach for material selection is given.

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.

Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Geotechnical Engineering and Engineering Geology
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