Expansive soils are prone to high volume changes due to seasonal variation in moisture content and may cause potential damages to geotechnical infrastructures. Hence, stabilization of expansive soil has become essential. In the past decades, stabilization of expansive soils using various chemical additives has gained significant attention. However, most of these studies have not addressed their effectiveness in terms of long-term durability and integrity. With this in view, the present study explored the efficacy of fly ash in combination with: (i) 5 M NaOH Alkali activator and (ii) Lime, as chemical additives at their optimal proportions, for stabilizing the expansive soil (Black cotton soil, BCS). While, most of the relevant studies in the past focused on unconfined compressive strength (UCS), the present work addressed the shear strength characteristics by conducting direct shear tests in the laboratory. Further, durability assessments were performed through wet-dry cycles tests on specimens cured for 28 days, focusing on mass loss variation. The results obtained indicate an increase in both cohesion and angle of internal friction, in stabilized soils, for both treatments. Notably, alkali-activated fly ash-treated soil has shown better resistance up to 5 W-D cycles compared to only 1 cycle for lime treated soil. Further, a reduction in cohesion and angle of internal friction is observed in alkali-activated fly ash-treated soil after the 2nd W-D cycle. From this study, it can be concluded that alkali-activated fly ash stabilization shows promising results for expansive soil stabilization, enhancing its potential durability and long-term effectiveness.