Recent interest in geopolymer concrete, a cutting-edge substitute for conventional Portland cement-based concrete, has increased because of its promising mechanical qualities and environmental sustainability. This study investigates the mechanical characteristics of geopolymer concrete made with fly ash, GGBS, & alkali activator solution as the only precursor materials. Three different mix calculations—one using fly ash, one using ground granulated blast furnace slag (GGBS), and one combining fly ash & GGBS—have been assessed. The combinations were maintained at a Na₂SiO₃/NaOH ratio of 2.0 & 3.0 after being activated with a 12M molarity NaOH solution. To ascertain their mechanical performance, concrete samples were created and evaluated for durability & compressive strength after 28 days. This study contributes to ongoing research and development efforts in sustainable building materials by examining the characteristics of geopolymer concrete and presenting test results based on our findings.