Assessment of Waste Printed Circuit Board Nonmetallic Powder in SBS-Modified Asphalt: Mechanisms and Economic Benefits

The rapid growth of electronic devices has led to significant environmental challenges and resource recovery pressure for discarded printed circuit boards (PCBs). This study reused waste printed circuit board nonmetallic materials (PCBN) to develop a high-performance, environmentally friendly asphalt binder and explored replacing a portion of styrene-butadiene-styrene (SBS) with PCBN. Adding 2% rubber oil enhanced the compatibility of PCBN in asphalt by 41.5% while also increasing the radius of gyration and diffusion coefficient of epoxy resins and glass fibers in PCBN. The performance of asphalt modified with 20% PCBN and 3% SBS was comparable to that of asphalt modified with 4% SBS, and effectively reduces SBS consumption by 1% while exhibiting excellent viscosity and antirutting properties. The optimal formulation was 20% PCBN + 3% SBS. Fourier-transform infrared spectroscopy (FTIR) analysis confirmed that the incorporation of PCBN into SBS-modified asphalt did not introduce new functional groups, suggesting that the improvement in mechanical properties is due to enhanced dispersion and interactions within the asphalt matrix. Additionally, the addition of rubber oil effectively mitigates the agglomeration of PCBN in asphalt. In China, replacing 1% SBS with 25% PCBN on typical highways can reduce costs by $12,132/km, yielding significant economic benefits. This study provides a resource utilization strategy for managing discarded PCBs.