Green cement replaces 50% of clinker with slag, a waste product from steel blast furnace. Apart from reducing CO2 emissions by half, green cement also has the advantage of being much more resistnt than traditional cement, especially along coastal environments! It is also cleaner for the environment in that the slag production from steel plants can be recycled as well as limestone resources preserved.
Here is another interesting development from cement manufacturers in Karnataka. Traditional cement manufacturing involves the process of converting limestone into clinker in a blast furnace. Clinker makes up 95% of cement. The article quotes that “in order to produce 1 tonne of clinker 1.5 tonnes of limestones is needed and in the process 0.5 tonnes of CO2 is released [in the atmosphere]”.