As previously noted, a significant portion of carbon emissions comes from the manufacture of concrete. More recently, this blog relayed a report in the Times UK that, at least according to some environmentalists, “big concessions were made for polluting industries such as steel and cement” at the EU summit in Brussels.
According to some building sector studies, it embodies 62% of carbon emissions associated with all construction materials. According to green technology correspondent Alok Jha, cement accounts for 5% of the world’s CO2 emissions – more than aviation.
We now learn from The Guardian that British engineers have developed a new environmentally friendly cement. Use of magnesium silicates means that no CO2 is emitted when heated. Since production process can operate at much lower temperatures – around 650C, there is less total CO2 emissions per tonne of cement produced. The “real kicker”…Novacem cement “absorbs far more CO2 as it hardens – about 1.1 tonnes. So the overall carbon footprint is negative.”
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Does anybody know whether the feedstock would include asbestos containing rocks? Asbestos dust has been a disaster in certain communities where the mined material wasn’t specifically used for asbestos.