ADVERTISEMENT
Green Concrete02-26-07 | News

'Green Concrete'




img
 

"There is no reason to believe that we couldn't begin to make cement materials that employ other chemistries that do the same thing but don't produce emission," said Hamlin Jennings, professor of materials science and civil environmental engineering at Northwestern University in Evanston, Ill.


The manufacturing of cement is a major producer of CO2 emissions. When limestone and clays are crushed to high temperatures the global warming gas is released. However, if the properties of nano-sizes particles in concrete are understood an end could be put to burning.

Researchers are seeking materials that will allow them to reduce the high temperatures necessary for cement production.

They have found that the strength and durability of concrete lies in the organization of spherical nanoparticles, namely calcium silicate hydrates.

If they can find alternative particles other than calcium silicate hydrates that will pack in high densities without the burning, they could potentially reduce the emission of carbon dioxide.

Although the science of concrete’s nanostructure is not simple to comprehend, it could potentially result in new concretes that could be made more durable and better for the environment.

Magnesium, for example has been identified as a possible replacement, however re-engineering the calcium silicate hydrate in order to get them to stack in a pyramid without heating in another challenge.

In addition, a 10 percent reduction in all concrete-related burning would accomplish one-fifth of the Kyoto Protocol goal of a 5.2 percent reduction in total carbon dioxide emissions.

Source: Discovery News

img