Abstract:
The concrete is made with concrete wastes which are eco-friendly so
called as Green concrete. The other name for green concrete is resource saving structures
with reduced environmental impact for e.g. Energy saving, co2 emissions, waste water.
Green concrete is a revolutionary topic in the history of concrete
industry. This was first invented in Denmark in the year 1998 by Dr.WG.
Why Green Concrete?
Huge impact on sustainability
Most widely used material on Earth
30% of all materials flows on the planet
70% of all materials flows in the built environment.
2.1 billion tonnes per annum.
15 billion tonnes poured each year.
Over 2 tonnes per person per annum
What is GREEN concrete?
Most people associate GREEN concrete with concrete that is colored
with pigment. However, it is also referred which has not yet hardened. But in
the context of this topic, green concrete is taken to mean environmentally friendly
concrete. This means concrete that uses less energy in its production & produces
less carbon dioxide than normal concrete is green concrete.
Engineers and architects have choices of the material and products
they use to design projects - when it comes to a building frame the choice is typically
between concrete, steel and wood. Material choice depends on several factors
including first cost, life cycle cost and performance for a specific application.
Due to growing interest in sustainable development, engineers and architects are
motivated more than ever before to choose materials that are more sustainable. However,
such choice is not as straight forward as selecting an energy star rated appliance
or a vehicle providing high fuel mileage.
Engineers and architects can compare materials and choose one that
is more sustainable or specify a construction material in such a way as to minimize
environmental impact? Recent focus on climate change and the impact of greenhouse
gas emissions on our environment has caused many to focus on CO2 emissions as
the most critical environmental impact indicator.
Life Cycle Assessment (LCA) is the parameter; the construction industry
should look into. LCA considers materials over the course of their entire life cycle
including material extraction, manufacturing, construction, operations, and finally
reuse/recycling.
Concrete is one of the world's most widely used structural construction
material. High quality concrete that meets specification requires a new standard
of process control and materials optimization. Increasingly, concrete is being recognized
for its strong environmental benefits in support of creative and effective sustainable
development. Concrete has substantial sustainability benefits.
The main ingredient in concrete is cement and it consists of Limestone
(Calcium Carbonate CaCO3). During manufacture of cement, its ingredients are heated
to about 800 - 10000C. During this process the Carbon Dioxide is driven off.
Approximately 1kg of cement releases about 900gms of Carbon Dioxide into the atmosphere.
Environmental Benefits to using Green Concrete Geopolymer concrete,
or green concrete, is part of a movement to create construction materials that
have a reduced impact on the environment. It is made from a combination of an
inorganic polymer and 25 to 100 percent industrial waste. Here is a list of 4 benefits
to using green concrete for your next project.
1. Lasts Longer
Green concrete gains strength faster and has a lower rate of shrinkage
than concrete made only from Portland Cement. Structures built using green concrete
have a better chance of surviving a fire (it can withstand temperatures of up
to 2400 degrees on the Fahrenheit scale). It also has a greater resistance to
corrosion which is important with the effect pollution has had on the environment
(acid rain greatly reduces the longevity of traditional building materials). All of those factors add up to a
building that will last much longer than one made with ordinary concrete. Similar
concrete mixtures have been found in ancient Roman structures and this material
was also used in the Ukraine in the 1950s and 1960s. Over 40 years later those Ukrainian buildings are
still standing. If buildings aren't constantly having to be rebuilt, fewer construction
materials are needed and the impact to the environment during the process of
making those materials is reduced.
2. Uses Industrial Waste
Instead of a 100 percent Portland cement mixture, green concrete
uses anywhere from 25 to 100 percent fly ash. Fly ash is a byproduct of coal
combustion and is gathered from the chimneys of industrial plants (such as power
plants) that use coal as a power source.
There are copious amounts of this industrial waste product. Hundreds
of thousands of acres of land are used to dispose of fly ash. A large increase in
the use of green concrete in construction will provide a way to use up fly ash and hopefully
free many acres of land.
3. Reduces Energy Consumption
If you use less Portland cement and more fly ash when mixing concrete,
then you will use less energy. The materials that are used in Portland cement require
huge amounts of coal or natural gas to heat it up to the appropriate temperature
to turn them into Portland cement. Fly ash already exists as a byproduct of another
industrial process so you are not expending much more energy to use it to create
green concrete.
Another way that green concrete reduces energy consumption is that
a building constructed from it is more resistant to temperature changes. An architect
can use this and design a green concrete building to use energy for heating and
cooling more efficiently.
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