Concrete has been around for millennia, but Terra CO2 thinks it has a better way to make the ubiquitous building material, and investors appear to agree.

The Golden, Colorado-based startup recently closed a $124.5 million Series B to help bring its low-carbon cement replacement to market.

Cement — the stuff that binds aggregate together to form concrete — weighs heavily on the climate. The CO₂ released by the chemical reaction that makes Portland cement, the most common type of cement, and the fossil fuels that typically power it accounts for around 8% of all carbon pollution. 

It’s why a range of startups have been exploring ways to get the same rock-solid results without the pollution. In addition to Terra CO2, Furno, Sublime Systems, Partana, and PHNX Materials all have different approaches to solving the problem.

SCM is a broad class of materials that serve to replace Portland cement without sacrificing any of the qualities that make concrete appealing. Terra CO2 makes a version of SCM that cooks widely available silicate-containing rocks until they melt into glass. The glassy powders react similarly to Portland cement.

The startup said that it’ll be using the new funding to build a massive facility near Dallas capable of pumping out 240,000 tons of its supplementary cementitious materials (SCM) annually.

Terra CO2’s new funding round was co-led by Bill Gates’s Breakthrough Energy Ventures, Eagle Materials, Temasek-backed GenZero, and Al Gore’s Just Climate. Barclays Climate Ventures, Cemex, Prologis, and Siemens Financial Services participated.

Today, Terra CO2 says that its SCM can replace up to 40% of the Portland cement used in concrete. It is also working on a next generation of its product that can completely displace traditional cement. Compared with Portland cement, the startup’s SCM generates 70% less carbon dioxide.