Researchers at Mepco Schlenk Engineering College in India have developed a concrete mix that absorbs CO2 and performs better mechanically than standard M35 concrete. The team replaced part of the fine aggregate with zeolite and part of the cement with bamboo biochar. Their best formulation, ZB5, used 50% zeolite and 1% biochar and reached a compressive strength of 38.49 MPa, about 7.5% stronger than conventional concrete. It also captured 1.2 grams of CO2 per day in carbonation chamber tests. Carbon uptake comes from the porous structure of zeolite and the carbon-rich biochar, which lets the material pull CO2 from the air while maintaining a dense cement matrix. The researchers suggest the mix could be used in pavements, highway barriers, and sewer pipes, especially in urban areas with high CO2 levels. The work is still at proof-of-concept stage. Long-term durability, real-world carbon uptake, and cost at scale need more testing before commercial adoption. Future studies will look at other biochar sources and performance in different concrete grades.
