The impact of adding orange peel waste on the engineering proprieties of fired clay bricks.

The construction industry urgently requires sustainable alternatives to conventional building materials to reduce resource depletion and greenhouse gas emissions. This study systematically investigates the incorporation of orange peel waste (OPW) as an eco-friendly pore-forming agent in fired clay bricks. Brick formulations were prepared by replacing clay with OPW at dosages of 0, 2.5, 5.0, 7.5, and 10.0%, and sintered at peak firing temperatures of 700 °C, 800 °C, and 900 °C. The physical, mechanical, and thermal properties were rigorously evaluated. The results demonstrate that increasing OPW content leads to a progressive reduction in bulk density alongside an increase in apparent porosity and water absorption due to organic matter combustion. Although the induced macro-pores decreased compressive strength, specimens containing 5.0-10% OPW fired at 900 °C safely exceeded international regulatory thresholds for non-load-bearing structural applications. Furthermore, the optimized bricks exhibited a substantial drop in thermal conductivity (down to 0.42 W/m K at 10% (OPW). Ultimately, a 5.0-10% OPW incorporation fired at 900 °C offers an optimal balance between structural integrity and enhanced insulation.