Saturday, October 22, 2011

Green construction? Try growing steel in your backyard

It’s not just for stir fry any more.

Brazil last month passed law creating incentives for the cultivation and processing of one of the world’s most overlooked green construction materials: bamboo.

It’s been used for construction for centuries in Asia, but has resurfaced as a natural alternative to steel for the construction of roads and in some cases even bridges. The Amazon region now has 18 million hectares of bamboo under cultivation. One of the world’s fastest-growing plants, it was until recently considered a pest because it spread so quickly.

Brazilian government leaders hope the law will help provide legal work to families living in rural poverty, which are the ones most likely to get mixed up with timber mafias and illegal deforestation. The new law will provide technical assistance, and low interest loans to family farmers interested in the idea, most of which will likely be developed in the state of Acre.

Engineers and architects have for nearly 50 years been pondering the idea of using bamboo as a replacement for steel. It’s only been the in the last decade or so that people they have seriously considered it in the context of reducing greenhouse gas emissions and limiting damage to the environment. Using bamboo instead of steel for reinforcing concrete in roads is a tricky process that still needs to be perfected. If bamboo isn’t treated right, it can expand due to moisture which can crack the concrete it’s supposed to be reinforcing.

But steel is pretty nasty stuff. The air and water pollution caused by the CSA steel mill in Rio de Janeiro (not to mention the problems caused by these guys) provide obvious reasons to look for alternatives. The often apocalyptic descriptions of living conditions near the “backyard” steel mills of Inner Mongolia in China are testament to just how useful bamboo could be greening the construction and infrastructure businesses.

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