Effectiveness of lime in stabilising subgrade soils subjected to freeze-thaw cycles

Periodic freeze-thaw conditions are known to alter the geotechnical behaviour of soils. Although lime stabilisation is used to enhance the mechanical properties of subgrade soils, Jordan lacks the experience with such utilisation where seasonal frost takes place during cold winters. An investigation is carried out on the impact of freeze-thaw cycles on the behaviour of lime-stabilised fine-grained soils widely available throughout the country. Five lime contents ranging from 0 to 8% are used to stabilise the soil. To study the effect of environmental factors on durability, soils are subjected to freeze-thaw cycles ranging from 0 to 20 and subsequently tested for unconfined compressive strength. Measurements show that lime stabilisation substantially improves the geotechnical properties of untreated soil. Benefits are measured in terms of reduced soil plasticity, higher optimum moisture content, lower maximum dry density, and higher unconfined compressive strength. Experimental results show that freeze-thaw cycles decrease the unconfined compressive strength of soil with further reduction as freeze-thaw cycles are increased. However, this effect is much higher on untreated soil as compared to stabilised soil. Findings of the present study confirm the appropriateness of lime for increasing the durability of cohesive subgrade soils exposed to freezing conditions. Such stabilisation offers lower life-cycle cost and enhanced pavement performance advantages to earthwork construction.