Sustainable pavement design has gained significant attention due to the increasing scarcity of natural aggregates and the environmental burden associated with construction activities. Construction and Demolition (C&D) waste offers a viable alternative material for pavement layers, promoting resource conservation and circular economy principles. This study investigates the feasibility of utilizing processed C&D waste in flexible pavement construction with an emphasis on structural performance, durability, and sustainability. The engineering properties of C&D waste aggregates, including gradation, strength, and stiffness characteristics, are evaluated and compared with conventional materials. Mechanistic–empirical design concepts are adopted to assess pavement response and long-term performance. Non-destructive evaluation techniques are considered to monitor in-service behavior and structural integrity of pavements incorporating recycled materials. Results indicate that, with proper processing and mix design, C&D waste can satisfactorily meet pavement design requirements. The use of C&D waste significantly reduces material costs, landfill disposal, and carbon footprint. This approach supports sustainable infrastructure development while maintaining acceptable performance standards. The findings provide practical guidance for integrating recycled materials into pavement design frameworks.