Effects of Wet–Dry Cycles on Strength and Microstructural Behavior of Expansive Soil Stabilized with Alkali-Activated GGBFS

Expansive soils pose various problems to the existing transportation infrastructures by causing damages to pavements, railways, and embankments due to differential settlement, and volume changes in soils. Therefore, expansive soil if used in pavements must be stabilized by using some suitable means. The present study investigates the strength and durability of expansive soil stabilized with alkali-activated GGBFS (ground granulated blast furnace slag). In order to accelerate the hydration process, an alkali activator of low molarity (i.e., 5 M NaOH) is used to stabilize the subgrade expansive soil. GGBFS and alkali-activated GGBFS were added in the proportions of 5, 10, 15, 20, 25, and 30% to check the improvement in the strength properties of expansive soils after different periods of curing. The strength properties of stabilized soil were assessed by conducting various laboratory tests like unconfined compressive strength (UCS) and California bearing ratio (CBR). Durability study was also done by subjecting the soil specimens to 12 wet–dry cycles. The utilization potential of alkali activated GGBFS has been assessed from the mechanical, mineralogical, and morphological properties of stabilized soil. It was found that alkali-activated GGBFS can be effectively utilized for highway subgrade and sub-base applications.