Development of Sustainable Precast Concrete Sandwich Wall Panels using artificial aggregates and mineral admixture

This study investigates the development of sustainable precast concrete sandwich wall panels using alternative materials. This study explores the partial replacement of natural aggregates with Lightweight Expanded Clay Aggregate (LECA) and marble waste aggregate while utilizing fly ash as a partial cement substitute. The experimental panels were constructed using self-compacting concrete mixes with varying proportions of these materials. The panels consisted of two steel fiber-reinforced concrete wythes joined by basalt fiber-reinforced polymer connectors, with expanded polystyrene insulation. Full-scale wall panels underwent flexural testing according to ASTM standards. The results indicate that alternative materials affect panel performance in terms of strength, ductility, and energy absorption. Panels with 20% LECA exhibited the best thermal performance, achieving a U-value of 0.363 W/m^2·K surpassing the energy code standards. The mixture containing 100% marble waste exhibited the highest flexural strength. Sustainable panels were estimated to be 28% cheaper in terms of raw material costs than conventional panels. The study achieved significant CO₂ savings of approximately 240 kg per ton of concrete when 30% of cement was replaced with fly ash. These findings underscore the viability of incorporating sustainable materials into precast concrete sandwich panels, offering a promising path toward more environmentally conscious and energy-efficient building practices.