Alkali-Activated Materials Reinforced via Fibrous Biochar: Modification Mechanisms, Environmental Benefits, and Challenges

Alkali-activated materials, as a low-carbon cementitious material, are widely known for their excellent durability and mechanical properties. In recent years, the modification of alkali-activated materials using biochar has gradually attracted attention. Fibrous biochar has a highly porous structure and large specific surface area, which can effectively adsorb alkaline ions in alkali-activated materials, thereby improving their pore structure and density. Additionally, the surface of the biochar contains abundant functional groups and chemically reactive sites. These can interact with the active components in alkali-activated materials, forming stable composite phases. This interaction further enhances the material’s mechanical strength and durability. Moreover, the incorporation of biochar endows alkali-activated materials with special adsorption capabilities and environmental remediation functions. For instance, they can adsorb heavy metal ions and organic pollutants from water, offering significant environmental benefits. However, research on biochar-modified alkali-activated materials is still in the exploratory phase. There are several challenges, such as the unclear mechanisms of how biochar preparation conditions and performance parameters affect the modification outcomes, and the need for further investigation into the compatibility and long-term stability of biochar with alkali-activated materials. Future research should focus on these issues to promote the widespread application of biochar-modified alkali-activated materials.