Utilization of chromium tanned leather waste in cementitious and gypsum composites for sustainable construction materials

This study explores the incorporation of chromium-tanned leather residues—chrome shavings and buffing dust—into cementitious and gypsum-based composites to address environmental challenges and enhance material performance. Chromium-laden tannery waste, a hazardous byproduct, was repurposed at varying proportions (8%–20%) to develop sustainable, energy-efficient materials. Key performance metrics, including compressive strength, flexural strength, thermal conductivity, and density, were evaluated. Results reveal that an 8% leather waste inclusion optimally enhances mechanical properties, achieving a compressive strength of 47 MPa and a flexural strength of 9 MPa, while reducing thermal conductivity from 0.7 to 0.1 W/(m°C). Higher waste content further improves thermal insulation but compromises strength and hardness due to increased porosity. Microstructural analysis shows improved bonding and reduced voids at optimal levels, explaining the enhanced performance. The composites’ reduced density also indicates potential for lightweight construction applications. This dual-purpose approach not only mitigates the environmental hazards of chromium waste but also develops lightweight, insulating materials suitable for non-load-bearing applications such as panels and insulation boards. The study contributes to global sustainability by integrating industrial waste into construction, reducing dependency on virgin raw materials, and promoting circular economy principles. Future research should focus on long-term durability, environmental stability, and scalability of these composites to ensure their viability across diverse construction scenarios. By addressing both waste management and material innovation, this research paves the way for greener, more sustainable construction practices.