Is Carbon-Negative Concrete Possible?

The race to address climate change has had a profound impact on the concrete industry as it attempts to lower its historically high embodied carbon. Low-carbon concretes are now available for most applications. They are not a one-size-fits-all low-carbon solution, however, which makes the specification process more challenging. Fly ash, for instance, can lower a concrete’s global warming potential (GWP) by 40% or more. But its use impacts curing time, and fly ash is a waste byproduct of coal-fired power plant emissions-control equipment, so some people are concerned about mercury content and empowering a dirty fossil fuel industry.

There is one material that has the potential to significantly reduce concrete’s embodied carbon, and that is biochar (a form of charcoal), but only in the right circumstances. One company trying this approach is Bioforcetech, whose OurCarbon biochar Solid Carbon is optimized for use as a concrete admixture. So what is Solid Carbon, and how could it help reduce the embodied carbon of concrete?