Concrete is used around the world to create sturdy, low-maintenance structures that withstand time and the elements. Now, concrete is coming inside, and you'd barely recognize it in its wide array of custom colors and designs that turn countertops and flooring into artistic endeavors.
The greenness of the material is a controversial topic. On the one hand, it's extremely energy efficient and can reduce power consumption. It produces little waste because it's custom-made for each project, and it's a zero-offgassing material, meaning it contains no toxic chemicals that evaporate under normal conditions. And producing concrete uses fly ash, a byproduct of the coal-burning industry that otherwise would just take up space.
On the other hand, producing traditional concrete creates a lot of CO2 -- about 7 percent of the world's CO2 emissions come from the process [source: Kriscenski]. Some companies, however, are now using a different type of cement in the process that reduces the CO2 contribution dramatically -- that concrete costs a lot more, but it's a truly green material [source: CNC].
The industry as a whole is instituting changes in manufacturing that should make it a more eco-friendly process in the future, so standard concrete could become a significantly green material going forward.