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.
