5
6 innovative startups that are kicking CO2 out of cement and concrete
(click.convertkit-mail2.com)
small nitpick: portland cement making is 150 years old.
we have been using hydraulic cements (crushed limestone, pozzolans etc.) since literally antiquity.
also this is really big because portland cement making and to a lesser extend also other types of cement making account for some 5% of global anthropogenic co2!
half of that is just from the chemical reaction of calcining the limestone and is thus independent of the used energy source.