This research investigates the potential of mechanosynthesis to transform inert waste mixtures into sustainable construction materials. Three waste streams were employed: recycled glass, recycled concrete, and excavated soils. Two alternative material formulations, F1 (50% recycled concrete, 30% recycled glass, 20% excavated soil) and F2 (60% excavated soil, 20% recycled concrete, 20% recycled glass), were developed. Cement pastes were produced by partially substituting cement (CEM I) with 50% of either F1 or F2. Characterization techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (ATR-FTIR), and mechanical testing, were performed. Cement pastes incorporating milled waste materials exhibited significantly enhanced compressive strength compared to their unmilled counterparts. At 28 curing days, compressive strengths reached 44, 47, 45, and 49.7 MPa, and at 90 curing days, they increased to 47.5, 50, 55, and 61 MPa for milling conditions of 200 rpm for 5 min, 200 rpm for 15 min, 400 rpm for 5 min, and 400 rpm for 15 min, respectively. In addition, F1 formulations showed higher compressive strengths than the reference CEM II and CEM III pastes. These results highlight the efficacy of mechanosynthesis in valorizing construction waste, mitigating CO₂ emissions, and creating environmentally friendly construction materials.