Recycled concrete, crushed plastics as an alternative to garden pot making.

farctatemountainousUrban and Civil

Nov 29, 2013 (3 years and 11 months ago)

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Recycled concrete, crushed plastics as an alternative to garden pot making.



Concrete

is a

composite

construction material composed primarily of

aggregate
,

cement

and

water
.
There are many formulations that have varied properties. The aggregate is generally a coarse gravel or
crushed rocks such as

limestone
, or

granite
, along with a fine aggregate such as

sand
.

Concrete is widely
used for makin
g

architectural structures
,
foundations
, brick/
block

walls,

pavements
, bridges/
overpasses
,
motorways/roads, runways,

parking

structures,

dams
, pools/
reservoirs
, pipes,

footings

for
gates,
fences

and

poles

and even

boats
.


Concrete has relatively high

compressive

strength
, but much lower

tensile strength
. For this reason is
usually reinforced with materials that are strong in tension (often steel). The elasticity of concrete is
rel
atively constant at low stress levels but
a start decreasing at higher stress levels as matrix cracking
develops
.

The environmental impact of concrete is a complex mixture of not entirely negative effects. A major
component of concrete is

cement
, which has

its own environmental and social impacts
.

The cement industry is one of two primary producers of

carbon dioxide
, a major

greenhouse gas
.
Concrete is used to create hard surfaces which contribute
to

surface runoff
, which can cause heavy soil
erosion, water pollution and flooding. The presence of some substances in concrete, including useful and
unwanted additives, can c
ause health concerns due to toxicity and radioactivity. Wet concrete is highly
alkaline and must be handled with proper protective equipment.

Concrete recycling is an increasingly common method of disposing of concrete structures. Concrete
debris was once
routinely shipped to

landfills

for disposal, but recycling is increasing due to improved
environmental awareness, governmental laws and economic benefits.



A

plastic

material is any of a
wide range of synthetic or semi
-
synthetic

organic

solids that are

moldable
.
Plastics

are typically

organic

polymers

of high

molecular mass
, but they often contain other substances.
They are usually synthetic, most commonly derived from
petrochemicals
, but many are partially natural.
[1]

The properties of plastics are defined chiefly by the organic chemistry of the polymer. such as hardness,
density, and resistance to heat, organic solvents,

oxidation
, and

ionizing radiation
. In particular, most
plastics will melt upon heating to a few hund
red degrees

celsius
.
[18]

While plastics can be made
electrically conductive, with the conductivity of up to 80 kS/cm in

stretch
-
oriented

polyacetylene
,
[19]

they
are still no match for most metals like

copper

which have conductivities of several hundreds kS/cm.

Plastics are durable and

degrade

very slowly; the chemical
bonds that make plastic so durable make it
equally resistant to natural processes of degradation. Since the 1950s, one billion tons of plastic have
been discarded and may persist for hundreds or even thousands of years.
[26]

Perhaps the biggest
environmental threat from plastic comes from nurdles,
[27]

which are the raw material from which all
plastics are made. They are
tiny pre
-
plastic pellets that kill large numbers of fish and birds that mistake
them for food.

Recycling

Thermoplastics can be remelted and reused, and thermoset

plastics can be ground up and used as filler,
although the purity of the material tends to degrade with each reuse cycle. There are methods by which
plastics can be broken back down to a feedstock state.

The greatest challenge to the recycling of plastics

is the difficulty of automating the sorting of plastic
wastes, making it

labor intensive
. Typically, workers sort the plastic by looking at the resin identification
code, al
though common containers like soda bottles can be sorted from memory. Typically, the caps for
PETE bottles are made from a different kind of plastic which is not recyclable, which presents additional
problems to the automated sorting process. Other recycla
ble materials such as metals are easier to
process mechanically. However, new processes of mechanical sorting are being developed to increase
capacity and efficiency of plastic recycling.



Concrete is very durable but with enough force, the concrete may b
reak instantly. Plastics property
display a compatible part of property that is needed to be the additive to added to garden pot making.
Plastics have a higher strength capabilities.

For making thus product. the researchers will choose a most clean way t
o help our environment and to
stop the pollution that palsitcs and concrete make. The researchers only choose recycled concrete for
making the product. For this, the resear
cher think that they will reduce the raw materials needed to
make a garden pot.