LaFarge, Chongqing
While government leaders argue about the practicality of reducing world emissions of carbon dioxide, scientists and engineers are seeking ways to make it happen.
One group of engineers at MIT decided to focus its work on the nanostructure of concrete, the world’s most widely used building material. The production of cement, the primary component of concrete, accounts for 5 to 10 percent of the world’s total carbon dioxide emissions; the process is an important contributor to global warming.
“If everything depends on the organizational structure of the nanoparticles that make up concrete, rather than on the material itself, we can conceivably replace it with a material that has concrete’s other characteristics-strength, durability, mass availability and low cost — but does not release so much CO2 into the atmosphere during manufacture,” said Franz-Josef Ulm…
The work is just beginning. Ulm estimates that it will take about five years, and says he’s presently looking at magnesium as a possible replacement for the calcium in cement powder. “Magnesium is an earth metal, like calcium, but it is a waste material that people must pay to dispose of,” he said.
There are a number of aspects of structural design that waste surprising amounts of energy. I must admit I hadn’t especially considered energy consumed and carbon produced in the manufacture of construction materials.
The research was funded in part by the Lafarge Group — which makes great sense — since they are the largest cement/concrete producer on the planet.
Making concrete is an especially energy wasting process. All of the mixing, crushing, conveying, milling and especially the reduction process in the kiln that has to heat up to 2700 deg F. The portland cement plant where my company does a lot of work is powered largely by coal. So any clean up in this process can save a lot of carbon dioxide going into the air. This article talks about replacing concrete with some other substance. For that to happen there would need to be some substance that is easily made that can be as cost effective and handled like concrete.
There are many areas (like Baja California, where I live) where concrete is the most-used housing construction material. Wood is simply too expensive here, and Mexico’s growing middle class wants the kind of decent housing that concrete construction makes practical for them.
Any development that either reduces usage of concrete for the same structural strength or that makes concrete more eco-friendly to use would find wide, fast acceptance down here. They’re already using foam-coating and other techniques that allow faster construction without sacrificing strength.
If MIT can find something that meets cjohnson’s criteria – cost effective and able to be transported and handled like concrete – it could have immediate, lasting effects on building in places like the Baja peninsula.
This article is a very good example of how the global warming hyperbole generates revenue for researchers. What these scientists are trying to do is find a new construction material that will be better than concrete in very specialized applications, such as pavement for freeways. There isn’t a snowball’s chance in hell that they will come up with something that will replace concrete in general use. Yet, by tying their research into global warming, they can get funding they might not have received otherwise.
Cement kilns are not going to go away; the demand for cement is very high and will remain so for many years to come.
Smith,
I skimmed the article and to be fair they don’t mention global warming at all. Based on the acknowledgements, it sounds like they’re getting pretty much all their funding from LaFarge, who probably aren’t that concerned with global warming either.
I for one am happy to be fooled that global warming is being taken care of.
THere is not really much new here. Magnesia cements have been around, are still being advocated, see:
http://www.tececo.com
Nanocem is a European Network, involving among other, the 5 largest cementproducers,
http://www.nanocem.net
Concrete is a necessary stable of industrial development, and the need to make it more sustainable is definitely there, one thing is the developed world, but even more important is developing countries: China presently has more than 50% of cement consumption, and the growth in production alone there last year (200 million metric tons) corresponds to twice the annual US production