The effects of termite mound soil, lime and particle size in sustainable bricks

Abstract

This study explores the formulation of sustainable bricks made of termite mound soil (TMS), lime, clay, sand, and rice husk, examining the impact of particle size, lime percentage, and TMS percentage on the physical and mechanical performance. Two different particle sizes (0.075 mm and 0.053 mm) were used and twelve mix ratios were tested to establish the best combination. The best formulation resulted in compressive strength of 7.56 MPa and water absorption of 14.15%, outperforming traditional fired clay bricks (strength 6.5 MPa and absorption around 18%). Particle size (0.053 mm) had a positive effect on packing density, lowering porosity and accelerating setting time. XRF results showed TMS to be pozzolanic (SiO₂+Al₂O₃+Fe₂O₃>70%), and SEM confirmed compact structure with C-S-H gel formation through lime-TMS reactions. Life cycle assessment (LCA) results showed that the developed brick can reduce the global warming potential by 95% (31.5 vs. 680 kg CO₂-eq per tonne) due to removal of firing step and local sourcing of raw materials.