Utilization of electronic plastic waste as fine aggregate with and without silica fume in concrete: experimentation and life cycle assessment

Abstract

The depletion of natural resources has created an urgent need to identify alternative, sustainable materials for construction. Simultaneously, the rapid global accumulation and improper disposal of electronic waste (E-waste), particularly in developing countries, have raised significant environmental and public health concerns. This study investigates the use of electronic plastic waste (E-PW) as a partial replacement for fine aggregate in concrete, with replacement levels of 5%, 10%, 15%, and 20% evaluated at different curing ages. While the inclusion of E-PW led to reductions in mechanical and durability performance compared to conventional concrete, these effects were mitigated by replacing 10% of the cement with silica fume (SF). The enhancement provided by SF demonstrated improved strength and performance in the E-PW concrete mixtures. According to SEM results, SF highlights the interfacial transition zone (ITZ) associated with E-PW in the OPC matrix. The best performing mix for blends containing E-PW and SF were M7 (5% E-PW + 10% SF), achieved a compressive strength of 37.69 MPa, a flexural strength of 5.36 MPa, and a splitting tensile strength of 3.91 MPa at 56 days, surpassing those of the reference concrete. An environmental perspective, life cycle assessment demonstrated that a 20% replacement of fine aggregates with E-PW reduced the overall environmental burden by 5.3% and lowered the global warming potential by 1.43%, equivalent to saving approximately 4–5 kg CO₂-eq per cubic meter of concrete. Hence, the findings support the potential for producing eco-efficient concrete by partially replacing natural sand with E-waste, contributing to resource conservation and environmental sustainability.