This study reports the findings of an experimental exploration for application of ground granulated blast furnace slag (GGBS) as a substitute for cement in various percentages. The research focuses on evaluating the effects of varying GGBS dosages, ranging from 0% to 50% with 5% increment for cement. To achieve this, concrete cylinders will be cast with different GGBS percentages and tested for compressive and split tensile strength. The goal is to find the optimum dosage of GGBS percentage that improves the mechanical properties of reinforced concrete (RC) slabs. Detailed analysis on the physical and mechanical properties of materials needed for M30-grade concrete will be carried out. Based on these observations made by experimentation, a mix design was formulated, for optimum dosage of GGBS by weight of cement. The slabs will be cast using the optimal dosage and compared with conventional concrete slabs to assess the impact of GGBS on structural elements. This study illustrates the slabs’ maximum load-carrying capacity and stiffness when subjected to two-point loading. It assists in selecting suitable materials for designing and constructing concrete slabs under such loading conditions, aiming to optimize resource use and minimize environmental impact. Microstructure analysis contributes valuable information on concrete quality, directly influencing the structural mechanical strength.