Biochar-added geopolymers

Previous studies have demonstrated that the incorporation of biochar into Portland cement composites can enhance several material properties. However, its effects on geopolymers have not yet been thoroughly studied. In this work, different formulations of metakaolin-based geopolymers containing various amounts of biochar were studied. The physical and mechanical properties of the obtained composites were investigated to evaluate whether comparable improvements could also occur in geopolymers. Results indicate that the addition of low biochar dosages (< 2 wt%) leads to an increase in compressive strength of about 15% after 28 days of curing, followed by a reduction in capillary water absorption, indicating potential improvements in durability. Conversely, higher biochar addition tends to reduce mechanical strength but contribute to greater dimensional stability and lower efflorescence formation.