Sustainable Cow Dung Bricks: An Innovative Approach to Eco-Friendly Masonry with Enhanced Thermal and Mechanical Performance

This study explores the development, characterization, and performance of sustainable cow dung bricks using locally sourced organic (cow dung) and mineral (clay, quartz sand, feldspar, lime) constituents for non-load-bearing masonry in India. Three blends with varying cow dung content (70%, 75%, 80%) were mixed, molded, air dried, and cured without kiln firing to reduce environmental impact. The bricks' mechanical properties—compressive strength, water absorption, bulk density, flexural strength, shore hardness, and modulus of elasticity—were systematically evaluated with complete statistical documentation (n = 6 replicates per formulation per test age). Microstructural features were investigated using Fourier Transform Infrared Spectroscopy (FTIR) and X-Ray Diffraction (XRD) to reveal the nature of organic-inorganic interactions and phase composition. The optimal 70% cow dung brick (M1) achieved a compressive strength of 4.2 ± 0.3 MPa (p = 0.002), water absorption of 18.5 ± 1.2%, and a bulk density of 1480 ± 45 kg/m3, meeting IS 1077/IS 3495 non-structural standards. FTIR and XRD analyses confirmed integration of organic matter with mineral phases and the formation of carbonation-derived calcite, contributing to strength development. Thermal conductivity was low (0.18–0.28 W/m· K), demonstrating 60-70% superior insulation compared to conventional fired bricks (0.6–1.0 W/m· K). Statistical analyses and data visualization were performed using Google Colaboratory and Python tools, ensuring rigorous and reproducible data interpretation. Material safety protocols for pathogen inactivation through sun-drying (48–72 hours achieving 90–99% pathogen reduction per literature) are presented as prerequisite for industrial-scale production. Durability assessment through IS 3495 efflorescence testing and climate-based application guidance establish appropriate use conditions for interior partitions in diverse Indian climatic zones. These results establish cow dung bricks as technically feasible, cost-effective, and environmentally sustainable alternatives for non-structural green building applications, supporting both circular economy principles and India's climate targets. The research underlines the potential for further optimization of unfired, bio-based masonry in sustainable construction, while identifying critical future research needs including long-term field performance validation and comprehensive microbiological characterization.