Tuesday, October 27, 2009

Ultra Concrete Solutions for Green Building and Climate Change

Development doesn't happen without concrete, the most used building material. The production of concrete emits 5-10% of the world's emissions.

Concrete has been synonymous with the development of civilization for millennia, since early masons first poured it on Roman streets. The material has literally shaped the world and literally, has stood the test of time. Its production, however, has proven costly to the environment.

The production of concrete emits 5-10% of the world's emissions. It is manufactured at a rate of 2.35 Billion tons a year enough for 1 cubic meter for everyone on the planet (Sciencedaily, 2007). If the process could reduce 10% of its carbon footprint, the end result would be one-fifth of the Kyoto Protocol's total global reduction target (5.2%). The immense heat, 1500°C, needed in cement production is the root cause of the extraordinary emissions. By using a different element other than limestone (which is mixed in with clay), scientists hope to eliminate the need for the high temperatures, and high-energy expenditures.

Nanotechnology has revealed that the particles of concrete structure together like apples on a fruit display. It is this configuration that gives the material its strength, and like a fruit display they can be packed tightly (most efficient, most strong) or scattered about (least efficient, less strong). Finding a better element that packs neatly, but requires less heat is the ultimate concrete goal. In doing so, development and growth of nations can continue using locally abundant minerals without unnecessary high carbon emissions.

Currently, there is no bigger way to cut emissions than increasing building efficiency. The heat losses a building suffers in the winter and the cost of air conditioning in the summer can account for the majority of the energy expenditures for any given country. Advanced concrete will be better able to insulate buildings, absorbing heat in the day and releasing it at night. Already 10 times stronger than the generation thirty years ago, concrete is now comparable to steel and aluminum, both of which create more carbon emissions per unit than concrete. Other advances include the ability to destroy pollutants that come into contact with a concrete structure and a type of concrete that can be applied to aging buildings that squeezes out moisture, thus enhancing structural longevity. Yes, concrete- the stuff durable green buildings are made of!

As promising as concrete is, like any technological solution accounting -in the form of life-cycle assessments- must prove impact on the environment is as minimal as possible. Development alters the face of the planet, forever, but it doesn't have to alter the climate forever as well. Ideally, a construction site will transport its materials using biofuel and power its equipment from renewable energy. It will compensate for the displaced foliage by planting replacement trees. Only with proper planning and foresight can the potential of a concrete jungle coexist with a green one.

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