Eco-engineered masonry from ferrosilicon slag-incorporated clay bricks for sustainable construction: mechanical robustness, thermal efficiency, and CO ₂ mitigation

The worldwide demand for sustainable construction materials is rising due to the escalating necessity for energy-efficient structures and environmental preservation. This study examines the thermal, mechanical, and economic properties of clay bricks augmented with ferrosilicon slag (FSS) as a replacement for traditional clay. The study assesses the potential of adding different quantities of FSS (10 %, 15 %, 20 %, and 25 %) to brick samples to reduce energy consumption, enhance thermal insulation, and lower CO 2 emissions in residential buildings. Mechanically, incorporating FSS significantly improved brick performance, with the FSS-15 % sample achieving a 34 % increase in compressive strength compared to conventional clay bricks. Simulations conducted using Design Builder software show that the FSS-25 % sample reduces cooling energy demand by 33.13 %, resulting in indoor operative temperature reductions of up to 1.47 K during the hottest months in Aswan, Egypt. The integration of FSS leads to a 24.53 % decrease in annual CO 2 emissions. Economically, the FSS-25 % brick presents the most cost-efficient option, with a simple payback period (SPP) of 2.26 years, demonstrating its exceptional energy conservation efficacy. These combined mechanical, thermal, and economic enhancements highlight the suitability of FSS-modified bricks as a durable, energy-efficient, and low-cost alternative for sustainable construction.