Large CO reduction and enhanced thermal performance of agro-forestry, construction and demolition waste based fly ash bricks for sustainable construction.

The exhaust gases in production of burnt clay bricks is responsible for greenhouse gases (GHGs) emission which increase the carbon footprint in the ecosystem. Here, we report carbon emission and thermal performance based evaluation of 8 ft. × 9 ft. × 8 ft. building. The bricks used in building construction are manufactured from fly ash, agro-forestry wastes, construction & demolition wastes (C&D), ground granulated blast furnace slag (GGBFS) using NaOH as activator in order to provide compressive strength in the range of 3-6 MPa with ambient curing at 30 °C for 28 days. Life cycle analysis (LCA) reveals the total CO emission for fly ash and burnt clay bricks estimated to be 43.28 gCO and 290 gCO per brick, respectively. Considering the current scenario, by replacing 1-2% of brunt clay bricks with agro-forestry waste, C&D waste based fly ash bricks can potentially reduce 0.5-1.5 million tons of CO emission annually. The embodied energy calculation shows fly ash based bricks consumes 10-15 times less energy as compared to burnt clay bricks. Thermal paremeters viz., U-value (0.5-1.2 W/mK), thermal conductivity (0.4-0.5 W/mK) show adequate insulation of agro-forestry waste based fly ash bricks highlighting its importance of thermal comfort, CO reduction along with sustainable and eco-friendly construction practices.