08/26/2026
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Injecting carbon dioxide into cement is a growing commercial strategy to store CO₂ and reduce emissions. But until now, no one had directly observed what actually happens chemically when CO₂ meets fresh cement paste.
Using real-time Raman spectroscopy, MIT researchers, led by Associate Professor Admir Masic in the Department of Civil and Environmental Engineering, captured the fleeting chemical reactions for the first time. They discovered a three-stage process where CO₂ temporarily suppresses the paste's alkalinity, creating a distributed silica gel network that ultimately produces a stronger, more uniform microstructure.
The result: CO₂-injected cement achieved 13 percent higher compressive strength at 24 hours compared to conventional mixes.
"Pointing a laser at CO₂-injected cement paste as it hardens allows us to visualize things that haven't been seen before," says Masic. The findings, published in the Journal of the American Ceramic Society, reveal the chemistry behind a technology already attracting commercial interest—and could help optimize it further.
https://news.mit.edu/2026/carbon-dioxide-rewires-how-cement-sets-0611
