Development of Alkali-Activated Artificial Aggregates Utilizing E-Waste

–  The global construction industry faces a critical shortage of natural aggregates due to the unsustainable rate of quarrying, leading to severe ecological degradation. Simultaneously, the rapid accumulation of electronic waste, particularly the non-metallic fraction (NMF) of printed circuit boards, presents a significant environmental challenge as these materials are traditionally non-biodegradable and difficult to recycle. This research aims to investigate the technical feasibility of synthesizing alkali-activated artificial aggregates by repurposing the non-metallic fraction of printed circuit boards and fly ash. The study is based on the hypothesis that the chemical synergy between the aluminosilicate precursors in fly ash and the glass-fiber-reinforced epoxy structure of NMF can produce a geopolymer matrix with mechanical properties comparable to natural crushed aggregates. To evaluate this, a systematic investigation was carried out involving the activation of precursors with an 8M sodium hydroxide and sodium silicate binary solution ( SS/SH of 2.5:1), followed by a dual-stage ambient and thermal curing regime at 100°C. The experimental results demonstrate that the 75-25 and 50-50 FA-EW formulations achieved Aggregate Impact Values of 24.44% and 22.30%, respectively, alongside Los Angeles Abrasion values ranging from 22.75% to 27.11%. These findings indicate that the synthesized aggregates comfortably satisfy standard requirements for road base and sub-base applications, which typically mandate limits below 30%. This work provides a technically robust and energy-efficient solution for diverting hazardous electronic waste from landfills while simultaneously addressing the global scarcity of natural construction aggregates through the principles of a circular economy.