Concrete is one of the most versatile and strongest materials for construction. But have you ever considered that it’s also an eco-friendly “green” material? Precast concrete, in particular, is environmentally friendly in a variety of ways.
Concrete Is Nearly Eternal
Concrete is tough and durable. Precast concrete, in particular, is even stronger because it’s manufactured in a controlled environment with a more exact mixing, molding and curing process. This results in greater strength and uniformity better resistance to elemental changes. It’s impervious to fire, water and termites. It doesn’t rust, rot or fade away over time.
Why is that a boon to the environment? It’s simple: when lumber rots, another tree is cut down. When a building burns everything is lost, so the environmental impact must be repeated to build a new one. But even without a catastrophe, any artificial materials still have a limited lifespan, so new materials must be mined or synthesized, with all the environmental costs involved.
Precast Concrete Has Few By-Products and More Efficiencies
Because of the accuracy possible with precast, there’s much less waste of the actual concrete when using precast than with poured-on-site concrete. The latter usually involves spillage and wasted remnants in the cement truck. Also, with plant casting, the molding process has significantly less waste because the molds are made of steel with exact dimensions in all directions. These durable molds can be used again and again, while poured-on-site cement uses wooden formwork that’s typically discarded after a single use.
Precast uses less scaffolding and can be erected more quickly, saving on both labor and transport costs. The fewer materials and workers driven to a construction site, the less gasoline is burned — and that means yet another emissions saver that might not be obvious at first. Precast can be installed with fewer weather delays and less on-site labor. Faster and more efficient construction means less on-site equipment noise and emissions.
Less Noise Pollution Yields Less Material Pollution
Modern trends in building aim to reduce sound transfer and create a privacy zone. Precast concrete, more than most any other material, prevents noise transfer into a building, avoiding the need for extra soundproofing insulation. Fewer necessary materials means a smaller carbon footprint.
A new process gaining popularity is a precast concrete panel that includes a pre-attached continuous layer of rigid foam insulation. This results not only in reduced noise, but also in the “green premium” of good thermal resistance, improving energy-efficiency.
What About Carbon Dioxide and Global Warming?
It’s true that manufacturing cement involves some carbon dioxide byproducts. What’s more, because concrete is such a versatile and popular building material — absolutely essential for high rise skyscrapers, bridges and more — some say it takes a toll on the environment when it comes to global warming. However, unless humanity lives only in caves, any assessment of the “green” nature of concrete must be made in comparison to the other available building materials.
Consider the alternatives. Steel requires mining iron ore, which is usually a dangerous and polluting process. Then it’s smelted, yielding noxious fumes. The production of steel uses vast amounts of energy because of the heat required. Plastics? They’re made from fossil fuels that can require environmentally dangerous deep-sea drilling. Wood may come from “renewable” trees, but the timber industry uses high-polluting gas chainsaws, must create roads through forests and uses gas-guzzling logging trucks to carry the trees many miles before ever arriving at a mill and then the lumber store, where it again must be transported to a job site. And as stated earlier, most of those materials do not last very long.
Concrete Is Here to Stay
Considering that modern, high-quality concrete can last for 100 years, the environmental impact is relatively small. Precast concrete technology is quickly nearing a point where it might be considered the greenest building material of all, and therefore an important resource as global culture moves in a more earth-friendly direction.