A new simple additive could turn concrete into an effective carbon sink say civil and environmental engineers from MIT.
The research team has revealed that introducing sodium bicarbonate – a new ingredient – into existing concrete manufacturing processes could significantly reduce the material’s carbon footprint without altering concrete’s bulk mechanical properties.
“The composite, a mix of calcium carbonate and calcium silicon hydrate is an entirely new material,” the researchers explained, with the resulting concrete setting much more quickly. “However, this research is still an ongoing effort. While it is currently unclear how the formation of these new phases will impact the long-term performance of concrete, these new discoveries suggest an optimistic future for the development of carbon neutral construction materials.”
Published in the journal PNAS Nexus, the authors of the study revealed new carbon dioxide sequestration pathways rely on the very early formation of carbonates during concrete mixing and pouring, before the material sets, which might largely eliminate the detrimental effects of carbon dioxide uptake after the material cures.
The research team demonstrated that up to 15% of the total amount of carbon dioxide associated with cement production could be mineralised during the early stages. Essentially this advances the concept of multifunctional concrete by incorporating the added benefits of carbon dioxide mineralisation during production and casting, they said.