Su, et al (2024) Microbial-induced carbonate precipitation (MICP) modified biocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More for low-carbon cementitious materials. Construction and Building Materials. https://doi.org/10.1016/j.conbuildmat.2024.138644

Concrete is a major contributor to global carbon emissions, with the cement industry alone responsible for around 8% of total anthropogenic CO2 emissions. To reduce the carbon footprint of construction materials, biochar, derived from organic waste, has emerged as a potential low-carbon filler for cement. However, biochar’s porous nature and low mechanical strength limit its use in construction.

This study investigates microbial-induced carbonate precipitation (MICP) as a method to modify biochar, improving its mechanical and structural properties when used in cement. MICP involves using bacteria to precipitate calcium carbonate within biochar pores, making it denser and enhancing its surface characteristics. The modified biochar was tested as a cement filler, and the results demonstrated several benefits.

MICP-modified biochar enhanced hydration rates in cement, improving both the compatibility of biochar with the cement matrix and the strength of the resulting material. The microbial process increased the formation of ettringite, a key hydration product, further boosting the mechanical performance. A biochar substitution of up to 10% in cement maintained compressive strength while reducing emissions.

Overall, MICP-treated biochar offers a promising solution for sustainable construction, combining biochar’s carbon sequestration benefits with improved material properties. Further research may focus on scaling the use of MICP-modified biochar in large-scale concrete applications to help achieve carbon-neutral construction goals.