<p>This study explores the influence of incorporating waste glass powder (WGP) via a combined replacement strategy involving both cementitious paste and coarse aggregates in lightweight concrete. The concrete formulation employs cold-bonded fly ash-derived artificial aggregates, with WGP incorporated at different proportions, achieving a maximum replacement of 17.5%. This dual substitution strategy seeks to reduce the environmental effects linked to conventional concrete manufacturing while improving the functional efficacy and sustainability of the resulting lightweight concrete system. For this, WGP was obtained through the grinding process of crushed waste auto glass. Cold-bonded coarse aggregate consisting of 90% of fly ash and 10% Portland cement was pelletized in a tilted pan to produce lightweight aggregate. The study focused on how this approach and WGP utilization affect the fresh, mechanical, and durability characteristics of the concrete together with the environmental aspect. The results showed that compressive strength of concrete rose up to 14.5% at 56&#xa0;days when using concurrent aggregate-paste replacement method. Moreover, thermal conductivity enhanced by 20.4% with the use of WGP content of 17.5% via using this approach. Utilizing WGP in concrete resulted in significant reductions in embodied carbon, embodied energy and production costs, eco-efficiency reaches its highest point approximately measured at 85% and lowest CO₂ intensity index by 10.7% compared to the reference mix, bringing vital insights into the sustainable application of WGP in cementitious materials.</p>