This study investigates the potential of utilizing recycled fines (RF) materials from construction and demolition waste by incorporating fly ash (FA) and ground granulated blast furnace slag (GGBS) as binder materials in the preparation of geopolymer for road applications. The experimental approach includes the characterization of C&D waste to assess its suitability as a raw material, along with the optimization of fly ash and GGBS proportions to achieve enhanced mechanical and durability properties of the geopolymer. Additionally, energy-dispersive X-ray spectroscopy (EDS) and field emission scanning electron microscopy (FESEM) were utilized to study the elemental level and microstructural changes occurring during the geopolymerization process. The findings indicated that increasing binder percentages, alkali concentration, and curing duration positively influenced the strength of the RF-FA-GGBS geopolymer. The study also found that, as per IRC:37–2018, all the geopolymer samples met the minimum strength requirements for a cement-stabilized mix, and their mass loss was well within the allowed range of less than 14% after 12 alternate drying wetting cycles. Finally, a leaching test was undertaken to explore the geo-environmental impacts of the geopolymer specimen, having optimum strength which revealed that heavy metal concentrations in geopolymer leachate are well within the limitations introduced by USEPA.