Experimental study of mechanical behaviours of lime-treated Quebec silty clay soils under freeze–thaw cycles

In cold regions, environmental factors significantly affect infrastructure such as roads, highways, and pipelines. Although lime and limestone products have been used to stabilise soil and enhance its engineering properties, their application in subarctic regions has been limitedly investigated. This study examines the effect of freezing and thawing on the mechanical responses of lime-treated soils retrieved from northern Canada. Samples were stabilised with lime and subjected to a curing period of up to 28 days to ensure consistent humidity and temperature. The cured samples were evaluated for unconfined compressive strength (UCS) and indirect tensile strength using a custom-designed measurement facility considering the number of freeze–thaw (F-T) cycles, loading rates, and curing duration. The double-punch test is shown to be effective in capturing samples’ brittle tensile behaviour. Our results demonstrate that both the UCS and tensile strength are significantly improved by adding lime to the soil. Both strengths generally degrade during the first ten F-T cycles. However, lime-treated soils begin to regain strength after ten F-T cycles. In addition, our test results show that the lime-treated soil is sensitive to exposure to ambient moisture. Nevertheless, the lime-treated soil still retains a much higher UCS compared with the natural soil.