Engineers have developed a special concrete made with carbonated solution to sequester carbon dioxide from atmosphere. This is based on using a carbonated — rather than a still — water-based solution during the concrete manufacturing process. The carbonated concrete offers potential to offset emissions from cement manufacturing.
The new approach, from Northwestern University, achieved a carbon dioxide sequestration efficiency of up to 45 percent (meaning that nearly half of the CO2 injected during concrete manufacturing was captured and stored). The resulting concrete is just as strong and durable as regular concrete.
A non-negotiable part of infrastructure, concrete is one of the world’s most consumed materials — second only to water. To make concrete in its simplest form, workers combine water, fine aggregates (like sand), coarse aggregates (like gravel) and cement, which binds all the ingredients together.
Now the scientists behind the development say that the carbon capture process is so simple that industry can implement it easily.
The new process will help to sequester carbon dioxide from the ever-warming atmosphere, it also results in concrete with uncompromised strength and durability. Carbon dioxide emissions from the cement and concrete industries are responsible for 8 percent of global greenhouse gas emissions.
According to lead researcher Alessandro Rotta Loria: “We are trying to develop approaches that lower CO2 emissions associated with those industries and, eventually, could turn cement and concrete into massive ‘carbon sinks.’”
There is further development work underway, as Loria clarifies: “We are not there yet, but we now have a new method to reuse some of the CO2 emitted as a result of concrete manufacturing in this very same material. And our solution is so simple technologically that it should be relatively easy for industry to implement.”
Carbonated water is created when water is infused with carbon dioxide gas under pressure.
For the development, the researchers leveraged the fresh concrete carbonation process. But, instead of injecting carbon dioxide while mixing all the ingredients together, they first injected carbon dioxide gas into water mixed with a small amount of cement powder. After mixing this carbonated suspension with the rest of the cement and aggregates, they achieved a concrete that actually absorbed carbon dioxide during its manufacturing.
The research appears in the journalNature Communications Materials. The article is titled “Storing CO2 while strengthening concrete by carbonating its cement in suspension.”
