This Startup Is Revolutionizing the Construction Industry with Carbon-Negative Concrete
As the urgency of climate change grows, the majority of attention is focused on shifting energy production from fossil fuels and electrifying transportation, from cars to buses to planes. Industry is the third most complex matter on the list, and concrete is a big part of it. Concrete is believed to be the most widely used substance on Earth after water. The production of cement, the key ingredient in concrete, accounts for a hefty 8% of global emissions.
CarbiCrete, a startup, has been working on one viable approach: carbon-negative concrete. Dr. Mehrdad Mahoutian and Chris Stern founded CarbiCrete, which received $17.3 million in Series A funding earlier this year.
Concrete in its current state
The key ingredient in concrete is cement, which emits CO2 in two ways: first, coal or natural gas are burned to generate the energy and heat required to achieve these rather high temperatures; and second, the chemical reaction of the cement compounds generates CO2.
Environmentally Friendly Concrete
CarbiCrete has been doing things a little differently. For beginners, they’ve eliminated cement entirely and replaced it with steel slag. They combine slag, aggregate, and water before pouring the mixture into forms to create concrete masonry units. The final stage is to cure the blocks so they harden and become fully functional. This occurs in an absorption chamber inside which CO2 is infused, causing yet again another chemical reaction; during the carbonation process, the CO2 is permanently captured and converted into stable calcium carbonates, filling the voids of the matrix and giving the concrete its strength. It takes 24 hours to reach full strength.
CarbiCrete is carbon-negative rather than carbon-neutral because it utilises CO2 gas derived from industrial vents through its absorption chambers. They are not producing CO2 from the start and are separating some that has been released into the atmosphere.
CarbiCrete claims that if a typical CMU-producing plant implements its technology, the environmental impact will be significant, with 20,000 tonnes of CO2 abated and removed, 4,400 cubic meters of water saved, and 33,000 tonnes avoided in landfills annually.
We’re still a long way from truly sustainable building technology, but even on a small scale, carbon-negative concrete is a positive step in the right direction.
