Mudbricks with tea grounds: A zero CO2 emission option for more sustainable and environmentally-friendly construction

Abstract

The traditional brick-firing process, characterized by high energy consumption and significant pollutant emissions, poses environmental challenges that require innovative solutions. This research addresses these challenges by reducing natural resource usage, energy consumption, and gas emissions through the production of mudbricks in which 5–10 wt% of the clayey soil is replaced by tea grounds. This approach uses waste products and efficient manufacturing techniques aimed at achieving zero carbon emissions. The meticulous selection and processing of organic waste draws inspiration from ancient practices in which plant residues were used to enhance the durability and performance of building materials. This study demonstrates that the inclusion of 10 wt% tea grounds enhances the workability of the clay by 15 %, as the lignin and hydrogen bonds in the tea rearrange the molecules, hardening the material in a similar way to the starch retrogradation process in bread. These mudbricks provide a 25 % improvement in thermal insulation compared to standard mudbricks, potentially reducing reliance on energy-intensive heating and cooling systems by up to 20 %. It also show a 30 % enhancement in impermeability relative to mudbricks made without tea grounds, with a 10 % increase in compressive strength.