MIT uncovers hidden chemistry behind CO2-injected cement achieving 13% higher strength
interestingengineering.comMIT researchers used laser imaging to watch how carbon dioxide changes cement hardening in real time. They found that injected CO2 temporarily captures calcium, which lets silicates form a silica gel network. When that gel reacts later, it creates a more uniform binding structure. Cement with CO2 equal to 1 percent of its weight showed 13 percent higher compressive strength after 24 hours compared to standard samples. The study challenges prior assumptions about how carbonation strengthens concrete. Calcium carbonate particles were not the main driver. Instead, the temporary silica gel pathway was key. The findings give engineers a way to optimize CO2 injection for stronger, lower-carbon cement without guesswork. The work came from MIT's Concrete Sustainability Hub and is published in the Journal of the American Ceramic Society.