Evaluation of freeze-thaw behavior of ground granulated blast furnace slag stabilized bentonite subgrade soils

This study investigated the freeze-thaw resistance of road subgrade soils stabilized with ground granulated blast-furnace slag (GGBFS). Within the experimental program, unconfined compressive strength (UCS) tests were conducted on pure bentonite and GGBFS-blended samples following standard Proctor tests and a seven-day curing period. The results indicated that GGBFS addition increased strength, with the optimum performance achieved at a 15% additive ratio. To evaluate freeze-thaw durability, pure and 15% GGBFS-stabilized samples were subjected to 3, 6, and 12 cycles (-23 °C freezing and +23 °C thawing). It was found that 15% GGBFS increased the strength by 2.66 times compared to unstabilized soil. Strength and weight losses increased with the number of cycles, reaching 66.51% and 2.03%, respectively, after 12 cycles. The findings demonstrate that GGBFS, an industrial by-product, is an effective and sustainable stabilizer for bentonite subgrades in regions exposed to seasonal freeze-thaw cycles.