Utilization of brick powder as a sustainable additive in concrete: Optimization of mechanical and thermal performance

This study investigates the effects of incorporating ground brick powder (GBP), derived from recycled demolition waste, into concrete mixtures as a partial replacement for natural fine aggregate. Three levels of modification of the GBP (5 %, 10 % and 15 % by weight) were tested to assess their influence on the physical, mechanical and thermal behavior of concrete. The experimental program included evaluations of workability, bulk density, compressive strength, tensile strength (splitting and flexural), elastic modulus, and thermal conductivity in two casting orientations. Microstructural analysis (SEM/EDS) was also performed to understand the role of GBP at the cement matrix level. The results demonstrated that 10 % GBP provided optimal mechanical performance, with an improvement of up to 54 % in compressive strength compared to the reference mix, while 15 % GBP yielded the best thermal insulation properties. The study also confirms that GBP improves the sustainability profile of concrete by reducing the reliance on virgin aggregates and lowering thermal conductivity. These findings support the use of brick waste as a viable functional additive in sustainable concrete, especially in applications where thermal performance or reduced material density is required. • Ground brick powder (GBP) used as partial fine aggregate in concrete. • 10 % GBP increased compressive strength by more than 50 % vs. reference concrete. • 15 % GBP reduced thermal conductivity by up to 31 % in casting direction. • GBP-modified concretes showed improved microstructure and ITZ quality. • Brick powder supports both structural performance and energy efficiency.