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There is some concern in the sustainable building community about the environmental qualities of concrete. The issue stems largely from concerns surrounding the production of cement, one of the key components in concrete. Cement production requires substantial amounts of energy, often coming from non-renewable fossil fuel sources. Additionally, the production process releases carbon dioxide into the atmosphere. These are valid concerns, and not to be trivialized. However, sustainability must be considered in the full light of a product’s lifecycle, and not just the production phase of its components.
In the case of concrete, energy requirements for transportation of concrete are low, because most concrete is produced locally from available sand and gravel. When used to create a passive solar building, concrete can produce a structure that is very energy efficient, resulting in overall energy savings when compared to a comparable wooden structure heated and cooled by conventional fuels. Concrete construction is highly durable as well, and will outlast traditional wooden structures many fold. Therefore the energy embodied in a single concrete structure must be compared against multiple wooden buildings. Additionally, concrete requires minimal maintenance, which further reduces energy inputs and operational costs of the building. Finally, at the end of its life cycle concrete can be reused as rubble for fill and road projects, not an insignificant point, as conventional wooden structures usually end their lifespan in landfills.
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