Sunday, 18 January 2009 09:51
There are a number of stories around about Carbon Negative cements.
Its an area that is worth paying attention to, as cement production causes about 5% of world CO2 emissions. Novacem's product is based on Magnesium Silicates and supposedly absorbs 0.6 tonnes of carbon per tonne of cement.
The Guardian has a good story on Novacem's product, and explains some of the numbers.
TecEco in Tasmania seems to have a similar product, based on Magnesia. Unfortunately it has been hard to figure out what TecEco really have, check the website to see what I mean. I questioned one of his diagrams because they appeared to be missing the overall CO2 budget, and received a lecture and numbers in weird units, that could either have been just obscure or designed to hide the overall numbers.
Another alternative is Hempcrete - a concrete made of Hemp and Lime. Apparently this is nothing new, and there are sixth century bridges in France built using this technique. (I need a reliable source for this!).
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