Wednesday, December 2, 2015

"Green" Concrete

With the push for environmentally friendly buildings and structures, more and more companies are demanding that their building be “green”. Cost and performance are still important factors, however, those concerns are being minimized by the new advancements in green concrete.
Green concrete is made up of some traditional materials along with other materials like aluminum can fibers, fly ash (which is a by-product of coal powered electric generation), and crushed concrete.  The aluminum can fibers are used to reinforce the concrete which leads to greater tensile strength, much like the way rebar is used to make concrete stronger, just on a smaller scale.  The use of aluminum cans in the concrete also reduces the amount of cans being put in landfills.
The use of fly ash in green concrete can replace the cement in concrete.  This is seen as an especially good thing for the environment because it eliminates the need for power plants that produce fly ash to dump the fly ash in special landfills as well as eliminate the need for cement plants that produce air pollution.  Fly ash can leach heavy metals into the environment if they are not properly stored, but when used in concrete, the fly ash no longer leaches heavy metals.  The heavy metals stay contained in the concrete itself, essentially rendering the heavy metals harmless.  The cement has heavy metals in it that can be leached into the environment until the concrete sets.  Therefore, by replacing the cement needed in concrete with fly ash, it essentially eliminates two potential sources of pollution or, as some would say, kills two birds with one stone.
The crushed concrete replaces the aggregate or crushed/small stone that is normally used in concrete.  This is good because it reduces the need to place old concrete in landfills as well as reducing the need to mine as much stone for the production of green concrete.
Therefore, green concrete reduces emissions from the cement plants, eliminates large areas normally needed to put old concrete, fly ash, and aluminum cans in landfills and reduces the amount of rocks (such as limestone, shale, sand, etc.) needed to produce concrete.

Written by Sean Combs, Legal Intern for the Public Trust Environmental Legal Institute of Florida.

No comments:

Post a Comment