Emma Clarke, writing for ClimateChangeCorp.com, reports on the development of more environmentally friendly concrete in The truth about...cement. Don't ask me to explain the chemistry behind it - chemistry was my worst subject - but here are the basic facts. Cement accounts for some 5 percent of man-made carbon dioxide emissions. Traditional cements emits about .6 tonnes of carbon for every 1 tonne produced, and that's not counting emissions from the fuel burned to heat the kiln.
A new type of cement called geopolymer cement produces only about a third of the carbon of traditional cement. A company called Zeobond based in Australia has managed to produce it in small quantities at a price of only 10-15 percent more than traditional concrete. Assuming there are some economies of scale involved, I would guess that this price could be brought even lower. So it looks like the tradeoff in increased price vs. reduced pollution could be attractive. But there are naysayers.
First, the stuff is untested in terms of its longevity and durability. But that is just a matter of time and testing - although it could be a while. The more difficult problem may be getting to one of the input materials for this new kind of concrete, something called aluminosilicates. According to the article, this "would require an overhaul of infrastructure for transporting and handling concrete." Perhaps this is one place where some rapidly growing developing countries could leapfrog past outdated infrastructure?
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