Freeze-thaw durability of clays treated with cement, slag and alkali-activated fly ash

This research examines the performance of cement-, cement-ground granulated blast furnace slag (GGBFS)-, and fly ash cement alkali-activated (FCAA)-stabilised high plastic clays by measuring mass loss, strength loss, and stress–strain behaviour under the impact of freeze–thaw (F–T) durability cycles. Twelve F–T cycles were conducted at freezing and thawing temperatures of −20°C and 20°C, respectively. For both the cement- and cement-GGBFS-stabilised clay mixes, the mass loss increased with the increase in F–T cycles, with a higher reduction rate up to 6 or 9 F–T cycles. Unconfined compressive strength (UCS) values reduced from the 1st to 6th F–T cycles, beyond which the values did not change significantly with additional F–T cycles. Final UCS at the end of the 12th F–T cycle for the cement-GGBFS-stabilised clays with 30% binder content and 50% GGBFS replacement was higher than 500 kPa. The mass loss and UCS measurements for most of the FCAA-stabilised clay mixes could not be recorded after the 1st F–T cycle because of the breakage of samples, indicative of insufficient durability. The results are helpful for adopting a suitable alternative binder for in situ ground improvement techniques such as deep soil mixing and jet grouting for stabilising high plastic clays in seasonally frozen zones.