"Sustainable Cement is Like Vegetarian Meatballs"
by Lloyd Alter, Toronto on 10.21.07
That's what Professor of Engineering Julian Allwood told Elisabeth Rosenthal of the International Herald Tribune. "The big news about cement is that it is the single biggest material source of carbon emissions in the world, and the demand is going up," ..."If demand doubles and the best you can do is to reduce emissions by 30 percent, then emissions still rise very quickly."
" The cement manufacturers are trying, and have invested millions of dollars in programs like the Sustainable Cement Initiative. They have improved efficiency significantly but are up against the basic chemistry: The chemical reaction that creates cement releases large amounts of CO2 in and of itself. Sixty percent of emissions caused by making cement are from this chemical process alone. The balance is produced from the fuel used in production, which may be mitigated by the use of greener technology. So to "go green," cement makers try to cut the fuel side of the equation."
The industry says "Because of our initiatives, emissions are growing slower than they would without the interventions." But they are still growing like mad. ::International Herald Tribune
image: vegetarian meatballs by seitti
Anyone know if this is referring to portland cement, or to fly ash cement?
I'm also wondering about terminology:
Many people use the word cement when referring to concrete. I believe concrete is an aggregate which uses cement as the binder. I think that concrete with a fly ash component simply uses the fly ash as a filler, resulting in lighter concrete and a use for what would otherwise be a wasted industrial byproduct. If "cement" manufacturing unavoidably releases huge amounts of CO2, that begs the question: is it possible to create concrete without cement? I don't think so, but I'm no expert. I'm a drafter for a structural engineering firm, and it seems to me that modern building techniques are entirely dependent on the use of concrete.
I'm not aware of any other material that could replace it.
I woner if the new material Grancrete would be more environmentally benign? It was developed by the labs at Argonne, and seems to offer some promise as a concrete alternative.
Just to clarify, concrete is mixed from cement. Cement is made by "cooking" limestone in a kiln, usually with coal as the main fuel.
Many cement companies add fly ash into the kiln (along with silica, and sometimes used tires, medical waste, hazardous waste, PCB-laden dredge spoils, you name it) when burning coal to make cement. While this is seen as beneficial by some, it mainly benefits the company's bottom lin
And the overall harm from HAPs released into the air from coal-burning (SO2, CO, mercury, arsenic, lead), the release of VOCs and sulphurs contained in the limestone, plus the harmful effects of mining both coal and limestone, and the landfilling of wastes trapped in the process, are devastating.
The headline of this article says it all. Good for Treehugger for keeping the focus on the cement industry's shameful greenwashing attempts.
Shameful greenwashing? I'm not sure it really constitutes that. It sounds like the cement industry is doing its meagre best and that the only way to significantly reduce emissions is to stop making cement. A drop in demand for cement seems even less likely than people giving up flights.
When the world trade center fell, My father (who is a structural engineer) was outraged to find that they build such a densly populated structure without concrete - he said it's a basic point of structural safety that steel structures use cement support. Is there really no alternative?
I never thought about this before; Does anyone have pointers to how much cement industrialized areas use? How does this scale to the rest of the world? Maybe there are alternatives suitable for urbanizing other regions which weren't an option in the west.
Unfortunately, I fear that to avoid sprawl, they may use even more cement than we did!
One might want to mention as cement sets up it absorbs CO2... a process that may not reclaim all of the CO2 used in the manufacture, but this process continues over the course of a few years as the cement gains strength.
Chemistry, people.
I believe that the contruction industry is also involved in reuse of old concrete to avoid mining and destruction of the environment in that way.
I am always interedsted in "professors" who offer great crisicms yet offer no alternatives. Say Prof! What's your solution?
We could all live in tents...what do you think?
So is there no hope for that greencrete stuff we heard about awhile back? And is that even available to the public?
Fly Ash cement can be used to displace portland cement in concrete. Using processed fly ash, one can achieve up to 70% (according to wikipedia). Displacing 70% of portland cement greatly reduces the CO2 emissions (probably about 70% of them, even without improving the efficiency of generating portland cement).
Does anybody know anything about geopolymer concrete? It sounds great, why isn't there more info on it?
Seven years ago or so I was at a conference on sustainable building and one of the presenters said that if all of the current concrete construction in the US were to utilize a fly-ash compound instead of 100% portland cement, the US would meet their Kyoto Protocol requirements.
I've never been able to verify that statement, but if anyone has any numbers to back that up, or disprove, I'd love to see them.
I like vegetarian meatballs.
With all the ballyhoo environmentalists make over lasting structures, why are they poo pooing cement? Ya lets build everything out of twigs and leaves.
I don't like TOFU. Would it be possible to use TOFU in place of concrete and therefore avoid having to use it as a food source?
Globally, the Portland industry manufactures 2 billion tonnes a year of cement - releasing 2 billion tonnes of CO2 into the atmosphere. (references available). Cement is the "grey powder" - yes, it is a component in concrete but relatively small % by weight.
The challenge the Portland industry faces is quite similar to that faced by the airplane industry back in the days before the turbo-fan (jet).
Everyone in the Portland industry is focused on making "incremental improvements" with existing basics... Inadequate strategy.
With 8 of the largest prop engines ever built, Hughes' Spruce Goose barely lifted off. With just 2 Rolls Royce 747-type turbo fan engines, it would have been a huge success. Engines rule.
The building industry needs a dissruptive technology. With a new engine. Not limestone.
I am aware of a nanotechnology silica based binding compound - different than Portland, stronger than Portland, manufactured at less than 100C, near zero emissions... proven over 15 years... due for market release in 2008. Developed by a world class PhD in Materials Science.
It will not replace Portland, but it will offer a truly green alternative for all pre-cast applications. Bricks, blocks, pavers, tiles, countertops, pipes, wall baffles... Complementary technology. Jet engines didn't replace propellor engines... they did shift market share a bit!
Apologies for the vagueness, but the lawyers are not finished their crossing t's and dotting i's.
I will respond to all inquiries as time allows.
The cavalry is on the ridge... If you can defer a project for a year, a "near zero" cement type product will be available.
I will ensure that "Tree Hugger" gets all the scoop as soon as we're ready to go public.
Best to all,
Al.
Ya lets build everything out of twigs and leaves.
I think I speak for many here when I say that you are, without doubt, the lamest and most anti-green commenter at Treehugger. Ever wonder why they keep you on? Because you're the anti-example for people to laugh at.
Is asphalt better then? Concrete lasts longer, is more expensive, and there is a lot of pollution in laying asphalt more often than concrete...the debate continues.
Seriosuly there is so much talk about reuse, buildings should be made from concrete, something that is going to last and be designed to be reused and re-purposed. Not OMG concrete is evil.
I swear anything that was/is ungreen and they try and change their product or process is deemed greenwashing. It just played into the nothing is ever good enough mindset.
Oh and quit posting anonymous.
Well Folks, there are other options floating around.
First, traditional cement and concrete continues to release CO2 as it cures, not absorb it, at least according to the research data I have seen.
Second, I am surprised that no one seems to have heard about the magnesium based concrete efforts. One such effort got a rather large award in a competition for green ideas held in Australia. The stuff is reported to absorb a huge amount of CO2 as it cures.
Third, on the subject of asphalt, it is about useless for structural considerations as it tends to get soft and deform over time. Even as road paving material it is massively inferior to the rubber asphalt compounds made from recycled tires, yet we still see people using the inefficient, less cost effective and short life cycle asphalt products.
By the way, I hope you are all getting involved in the day of environmental action on Nov. 3. Stepitup2007.org is organizing events all over the country, and I will be a guest speaker at one of the events here in Ohio.
Cement ABSORBS CO2 as it cures. If it was releasing CO2 it's molecular structure would get weaker over time, and as it is, in reality, it gets stronger as it cures.
Someone needs to kick the stupid out of environmentalism. We could get stuff done if we were not so ill-informed.
Yes a very intelligent and civil comment....
"Ya lets build everything out of twigs and leaves." = neither civil, nor intelligent
Thank you for your continued demonstration of what I described. Every court needs its fool.
Then flag it as a problem and let it go.
Why would I flag it as a problem? Like everyone else here, I enjoy that you come here and provide a great anti-example to represent people who hate treehugging and everything it's about. Post away.
1921 Alpha Portland Cement Ad Build Garage
An original advertisement for Alpha Portland Cement Co. Title: Concrete Garages Built with House Source: February 1921 The American City Condition: Very ...