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Green Cement Absorbs Carbon
Peace Corps Online writes "Concrete accounts for more than 5 percent of human-caused carbon dioxide emissions annually, mostly because cement, the active ingredient in concrete, is made by baking limestone and clay powders under intense heat that is generally produced by the burning of fossil fuels. Now Scientific American reports that British start-up company Novacem has developed a 'carbon-negative' cement that absorbs more carbon dioxide than it emits over its life cycle. The trick is to make cement from magnesium silicates rather than calcium carbonate, or limestone, since this material does not emit CO2 in manufacture and absorbs the greenhouse gas as it ages. 'The building and construction industry knows it has got to do radical things to reduce its carbon footprint and cement companies understand there is not a lot they can do without a technology breakthrough,' says Novacem Chairman Stuart Evans. Novacem estimates that for every ton of Portland cement replaced by its product, around three-quarters of a ton of CO2 is saved, turning the cement industry from a big emitter to a big absorber of carbon. Major cement makers have been working hard to reduce CO2 emissions by investing in modern kilns and using as little carbon-heavy fuel as possible, but reductions to date have been limited. Novacem has raised $1.7M to start a pilot plant that should be up and running in northern England in 2011."
No mention in the article of the strength of the new material. How would this compare to regular concrete?
Not only no mention of the strengths, or the weight of absorption, but also no mention of the huge body of knowledge of cement that the building industry has amassed over time.
There is a cement for every purpose, using formulas worked out over hundreds of years, virtually every aspect of it is well understood.
Who knows about the new stuff?
Who builds the first bridge, or sky scraper that will get heavier (by 2/3rds according to the article) as it ages?
And what about the fossil fuels used to make the cement? Do they remain the same?
People are going nuts looking for CO2 emission sources in all the wrong places. Look at the chart of CO2 emission sources. Soda Ash production (the category that includes cement) is WAY down the list. Microscopic.
http://www.epa.gov/climatechange/emissions/co2_human.html
The effort would be better spent building Nuclear generation plants and figuring out what to do with spent nuclear fuels, because a 10% reduction in CO2 emission from fossil fuels would totally swamp any reduction due to cement manufacturing.
Of course the same scare tacticians who see the CO2 boogie man under every bed also won't let us build Nukes. So we cast our hopes in cement, literally and figuratively.
Sig Battery depleted. Reverting to safe mode.
the lowest bidder will likely be the one with the smallest CO2 output.
I see where this is going.
Never mind the real costs. Lets set building prices based on some half baked idea that CO2 emission is more dangerous than anything else that could possibly happen.
Sig Battery depleted. Reverting to safe mode.
We don't know exactly, however it has been established beyond any reasonable doubt that human activity is a major contributor.
Really? Then I guess that my doubts are not reasonable, and I should not worry that IPCC numerical models predictions are more and more challenged by experimental data, and by dissidents within the IPCC itself...
It may have been beyond reasonable doubts until about 2005. I do not think it is anymore, the recent scientific advances and newest global data are not so supportive of the idea that man-produced CO2 is responsible for the bulk of global warming, and even less of the more catastrophic predictions for future climate change...