Carbon Conscious Concrete

Concrete is integral to our modern society. It allows us to build walkways and roadway. It is the major component in many high-rise buildings that we live and work in (and is the foundation in many single-family homes. It is strong, robust and relatively inexpensive. For these reasons and many more, you can start to see why much of our built environment is composed of concrete. But what are its environmental costs? (hint: concrete is the third highest emitting industry in the world.)

Setting aside the fact that water is required to mix concrete, let's take a look at the next most important ingredient: sand. The 99% Invisible podcast took a deep dive into the world of sand. The take home: not all sand is created equal and it is becoming increasingly difficult to fill the demand for sand, especially in highly urban areas. Add in the emission cost of moving the sand from the place it is mined to the location it needs to be used. And then consider the quantity... (Have you ever lifted a single sandbag?!) The takehome: it's not a very pretty picture.

Enter: CarbonBuilt, a company looking to change concrete's environmental impact. How? By embedding carbon dioxide into the concrete. Winner of the 2021 NRG COSIA Carbon XPRIZE, the CarbonBuilt team has shown an effective way to add CO2 to the concrete mix. How much? Quote: " ...the team successfully injected nearly three tons of CO₂ into more than 10,000 concrete blocks as they cured." That's certainly a significant offset. Check out their precess below:

Of course, it will be important to see how this works at scale and if it is as financially viable as traditional concrete. But that $20M prize will probably help them out. Congrats!