This thesis explores how plastic residues from Waste Electrical and Electronic Equipment (WEEE) recycling, usually destined for incineration or landfill, can be transformed into injection-molded building components. It focuses on reinforcement spacers embedded within the internal shearing layer of concrete, offering a realistic application for low-grade, contaminated polymers in architecture.

The research follows a dual-track methodology: bottom-up material development and top-down product design, connected through iterative feedback. The material track reproduces key mechanical recycling steps at lab scale density separation, color sorting, FT-IR, and DSC analyses, to formulate injection-moldable blends using carbon black Polypropylene/Polyethylene (PP/PE), Polypropylene (PP), and Polystyrene (PS).

In parallel, the design track generates and evaluates spacer prototypes using a custom multi-criteria optimization tool tailored to material constraints. The final outcome confirms the structural feasibility and fabrication compatibility of using these recycled polymers. The project demonstrates the architectural potential of overlooked plastic waste through process-driven reuse.