A new study from MIT and CarbonCure Technologies explains the chemical mechanism behind CO2 injection in cement. The research shows that adding CO2 equivalent to one percent of cement weight increases compressive strength by 13 percent after 24 hours. Using Raman spectroscopy, the team found that CO2 reacts with calcium to form calcium carbonate, which then triggers a silica gel network that leads to a more uniform distribution of calcium silicate hydrate, the main binding phase in cement. This improved distribution, not the calcium carbonate itself, drives the strength gain. The findings help optimize carbon mineralization technologies already used commercially to reduce concrete's carbon footprint. A better understanding of the chemistry could support development of stronger low-carbon cement and concrete products. This is relevant for anyone tracking industrial decarbonization, carbon capture utilization and storage (CCUS), and emissions reduction in hard-to-abate sectors like cement production.
