Cement is responsible for about the same amount of greenhouse gas emissions as all of the cars on the road today worldwide. Cement has been widely considered one of the most difficult materials to decarbonize and has even been called out as the reason why we need point-source CCS. We have invented a way to make carbon-negative Portland cement that does not rely on point-source CCS and is identical to conventional cement and, most importantly for impact, is lower in cost. Simply put, our process will turn one of the most intractable climate problems into a carbon-negative climate solution.