Sublime Systems

Cement holds the modern world together, but it lacks the allure of high-tech materials. “The stuff is gray,” says Yet-Ming Chiang , a professor of ceramics and materials science at the Massachusetts Institute of Technology. “You would be forgiven for thinking it’s kind of dull and boring.” But it’s not for Chiang and Leah Ellis, cofounders of Sublime Systems . They say finding a new way to make cement is necessary to solve one of the planet’s most pressing problems: the carbon dioxide emissions that are driving climate change. Cement, or calcium silicate hydrate, binds rocks and sand together to form concrete. Worldwide, cement companies make roughly 4 billion metric tons (t) of the stuff annually, according to the US Geological Survey. By some estimates, cement production accounts for as much as 8% of global CO 2 emissions . About half that massive belch of CO 2 is an unavoidable