Eco-Friendly Bio-bricks: Development and Characterization Using Locally Available Natural and Agricultural Waste Materials

This study explores making sustainable bio-bricks using materials readily available in the local environment: clay, sand, lime, termite mound soil (TMS), and rice husk. The present study examined these materials, both individually and when combined, to understand their microscopic structure, mineral composition, and thermal stability. Scanning electron microscopy (SEM) revealed a dense, tightly bonded structure in the composite bio-brick, with well-fitted particles enhancing its strength. X-ray diffraction (XRD) confirmed this, identifying the main crystalline phases in the bio-brick: quartz, kaolinite, portlandite, and amorphous silica. The presence of these minerals suggests excellent chemical compatibility among the components, enabling the material to undergo effective reactions that promote hardening and strength development. Thermogravimetric analysis (TGA) revealed the material's thermal stability, showing it remains stable even above 540°C. This composite performs well under high temperatures, but it excels when the mixture is precise: 45% clay, 22% sand, 6% termite mound soil, 12% lime, and 15% rice husk. At these ratios, it absorbs the least amount of water—just 14.15%—and achieves a compressive strength of 7.56 MPa. Importantly, these bio-bricks demonstrated a significant reduction in global warming potential, decreasing CO₂ emissions by 95% compared to traditional bricks. This study highlights the potential of utilizing local resources to produce sustainable building materials, contributing to eco-efficient construction practices and reducing reliance on non-renewable resources. The findings suggest that bio-bricks could offer a viable alternative for low-income housing, fostering local economic development and promoting environmentally sustainable building solutions.