Limestone in traditional cement recipes are releasing more than .05kg (.11lbs) of carbon dioxide into the atmosphere for every 1kg (2.20lbs) of cement. The releases of the carbon dioxide levels are responsible for approximately 5% of global CO2 emissions, double the amount produced from the aviation industry.
A handful of cement production companies are trying to adjust their process of cement production to lower CO2 emissions by approximately 70%. Unfortunately, limestone is still implemented yet reduced in cement recipes used by these few companies. The goal is to ultimately eliminate limestone all together, but may take some time to find a substitution.
A synthetic version of wollastonite, a low-carbon alternative to limestone, may become a possible solution. However, wollastonite can be a more expensive and scarce, but it carries a minor amount of calcium in comparison. Another benefit of implementing wollastonite, is that the cement produced with the mineral may eventually produce “negative emissions” concrete. The material will absorb CO2 during the curating phase, much like normal cement, without producing any positive emissions.
Check out QUARTS for more details on how a few cement production companies are changing the chemistry of today’s cement.