How Eco-Friendly is Concrete?(downloadable pdf version of this article)
Eco-Friendly Concrete (116 KB)
You probably would not be surprised to learn that the number one most consumed substance on Earth is water. However, you might be a little taken aback by the runner up in this category…concrete. That’s right, according to the Pacific Southwest Concrete Alliance the second most used material on the planet is concrete. But if you take a moment and think back on your day, maybe you shouldn’t be quite so astonished. Concrete is everywhere. It is in the foundations of our homes and garages, the sidewalks we walk on, the roadways we drive on, the buildings we work in…it is absolutely everywhere.
At first glance, concrete may seem to be a responsible choice for the eco-conscious consumer. After all, it is made up of little more than cement, sand, gravel, and water. That sounds like a harmless enough combination, right? Not quite. Cement is extremely energy intensive to produce. The production of Portland cement (the most common type of cement) involves heating a mixture of limestone and a second raw material (clay, sand, iron, etc.) to 1450 degrees Celsius, or about 2700 degrees Fahrenheit. As you can imagine, this requires incredible amounts of energy, and it also releases an outrageous amount of CO2 (a harmful greenhouse gas) into the atmosphere. The mining of other raw materials, such as sand and gravel, is also far from a green practice as it contributes to further depletion of the Earth’s natural resources.
Fortunately, there are several “green” alternatives to traditional concrete.
- High-volume fly ash concrete – a mixture of fly ash, lime, and water creates a product with similar characteristics to Portland cement. This type of concrete requires 25% less cement, and it utilizes fly ash – a by-product of coal-burning power plants typically thrown into landfills.
- Blast furnace slag – when mixed with lime and water, it also creates a strong product with similar characteristics to Portland cement. It comes from blast furnaces that make iron, and may be more readily available than fly ash.
- Carbon concrete – this is made by turning a by-product from oil refineries into a binder that replaces cement.
- Foam Crete – as the name implies, this concrete is foam-based, and is less energy intensive to manufacture.
- Ceramicrete and Glass Fiber Reinforced Concrete (GFRC) are both two times stronger than traditional concrete, so you can use less of it for your project.
Another great way to reduce the environmental impact of concrete is to use recycled aggregate materials instead of sand and gravel (which have to be quarried). These items can include recycled glass, old tires, scrap wood, plastic, and more! New and innovative products are constantly being introduced, if you know of any others please let us know!
We hope you can use some of this information with your new garage plans to make your garage building project a little more eco-friendly.