According the article, they didn't use calcium carbonate directly. They use quicklime (Calcium oxide) which must be mixed in at very hot temperatures.
When a crack forms, that stuff melts and forms calcium carbonate that seals the crack.
It gets hot when you mix it.
According the article, they didn't use calcium carbonate directly. They use quicklime (Calcium oxide) which must be mixed in at very hot temperatures.
When a crack forms, that stuff melts and forms calcium carbonate that seals the crack.