Brimstone, a startup that produces zero-carbon cement, has raised one of the biggest Series A rounds on record for materials science startups.

The firm raised $55M in a Series A funding round co-led by Bill Gates’ Breakthrough Energy Ventures and venture capital firm DCVC, it announced Thursday. The round closed in March and follows a $5M seed investment in November. The Series A round was oversubscribed with $200M worth of investor interest despite Brimstone’s pre-revenue status, The Real Deal reported.

Brimstone’s co-founders, CEO Cody Finke and Chief Technology Officer Hugo Leandri, want to cut notoriously carbon-emitting cement from construction, instead replacing it with a climate-friendly alternative.

"What sets Brimstone apart in the space is that we are building a new process to make Ordinary Portland Cement carbon-negative, which will be both lower cost and produce the exact same material trusted by builders for 150 years,” Finke said in a release.

Cement is a key concrete ingredient but is also a problematic component for real estate’s greenhouse gas emissions: Along with concrete, it accounts for 7.5% of the planet’s carbon dioxide emissions, putting it on par with cars.

The startup’s Portland cement crushes calcium silicate rock — a material that makes up half of the Earth’s crust — before using a leaching agent to extract the calcium, CNBC reported.

“If the planet is to get to zero-carbon on any sort of meaningful timeline, we cannot get there unless we fix cement’s CO2 problem,” Fifth Wall partner and co-lead of the Climate Tech Investment team Greg Smithies said in a release. “Brimstone is the only company in the world that can make cost-competitive zero-carbon cement. It’s truly a game-changer.”

Because developers typically purchase concrete, Brimstone will have to talk to structural engineering firms and concrete suppliers as it advances its mission, Finke told The Real Deal.

Brimstone recently closed on a site close to Reno, Nevada, where it will build a pilot plant. It is actively seeking chemical engineers and people in the cement industry, as well as a real estate developer to partner with on a project.