Although it’s being used since the late 1800s, the Portland cement (OPC) is guilty for a large amount of carbon dioxide spewed in the atmosphere by its manuacturers. The latest recipe comes from Drexel and uses an industrial byproduct to make the cement greener.
The byproduct is called slag. It and limestone, a common mineral, do not require heating, hence energy, to produce, and are much greener than what’s currently being used. Actually, Drexel’s Alex Moseson said that the alkali-activated cement they invented resembles more like the one Romans used thousands of years ago, and which contained volcanic ashes.
For those who don’t know yet, the Roman cement still exists in Italy’s numerous ruins and antic buildings, as a proof of their advanced technology at the time. The Egyptians also used forms of alkali-activated cement, and so did the Russians in the 50’s and 60’s.
Drexel’s cement contains 68 percent unfired limestone, which is a low-carbon dioxide resource, while the Portland cement only contains 5 percent of that limestone.
So the house you’re eventually going to build for your family isn’t green just because you insulate it better than your neighbor or install more solar panels than everyone else, it’s also got to be green starting with the materials you choose for building it in the first place. Just an information about such a low-carbon cement is enough to save hundreds of kilograms of carbon dioxide spitted into the air… only because you didn’t know about it.