In a new paper, MIT researchers investigate the carbon uptake of all pavements in the United States.
The study finds that the carbonation process could offset 5 percent of the CO2 emissions generated from cement used in U.S. pavements. Much of those offsets, the researchers find, could occur years after pavements have been demolished, especially in states that use composite pavement designs.
Though all concrete experiences carbonation to some degree, the magnitude depends on how large the concrete surface is that's exposed to air. That can make estimating carbon uptake challenging. While many buildings use concrete, the exposure of that concrete varies widely by design. In pavements, it’s a different story. “There's a big opportunity for [carbon uptake] in concrete pavements,” says AzariJafari, “because usually the surface-to-volume ratio of concrete pavements is 10 times bigger than the surface-to-volume ratio of concrete elements in a building.”
https://news.mit.edu/2021/unravelling-carbon-uptake-concrete-pavements-0126
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