Sustainable biochar-based bricks: evaluating the mechanical, thermal and durability properties of paddy stubble biochar for structural applications
摘要
The current study investigated the potential use of paddy stubble biochar (PSB) as an eco-friendly alternative in the manufacture of bricks. Bricks prepared using different combinations of PSB, PSP (paddy stubble powder), lime and water were assessed for their physical, mechanical and durability properties. An optimal mix comprising approximately 35% PSB, 35% PSP and 30% lime offered a balanced combination of mechanical strength, water absorption and resistance to efflorescence, outperforming other tested formulations. The compressive strength of PSB based biobricks reduced with greater percentage composition of PSB. The strength reduced to 600 kPa for bricks constituted by 35% PSB, while 300 kPa for those with 55% PSB. Water absorption potential varied from 28% for bricks with 15% PSB to 20% for those with 35% PSB. The thermal conductivity decreased from 0.1807 to 0.1724 W/mK with increasing content of PSB, which indicated improved thermal insulation. Efflorescence test revealed no visible salt deposits, and plastered bricks exhibited improved fire resistance. The microstructure analysis revealed interconnected pores that enhanced thermal insulation, while reducing the compressive strength of PSB-based bricks. The bulk density varied between 750 kg/m3 for bricks containing 35% PSB and 500 kg/m3 for those with 55% PSB, testifying the lightweight nature of biochar-based bricks. Although the PSB-based bricks with reduced compressive strength cannot be recommended for structural purposes, they could be promising for non-structural applications such as partition walls or insulation materials. Further studies should focus on optimizing mix proportions, enhancing fire resistance and exploring hybrid materials to enhance the durability and performance of PSB-based bricks for wider applications as a renewable and cost-effective alternative for construction materials.