The Role of Concrete in Construction
Concrete
is a strong element and a vitally important thing which is used in several
individual and commercial buildings. It solidifies and hardens after mixing
with water and placement due to a chemical process which is known as
hydration. It binds other building
materials together. It is a material extensively used in the construction
process and is made by mixing aggregate, cement, small stones, sand, gravel and
water. All the components bond together, to create a stone-like material.
The
Romans invented the hydraulic cement-based concrete. The British improved upon
it and popularized it in the modern world. The Pantheon in Rome is one of the
finest examples of Roman architecture that has survived to this day and has a
42-meter-diameter dome made of poured concrete.
USES
Concrete
is used to make pavements, architectural structures, foundations, motorways,
roads, and bridges, overpasses, parking structures, walls and footings for
gates, fences and poles. It is most used man-made material.
HOW IT WORKS
The
material grows together from a moldable liquid into a hard, rigid solid. In the
world today, concrete has become a fact of modern life. 6 billion tons of concrete
is used around the world each year. The addition of sand, fine aggregates and
coarse aggregates of up to a few centimeters makes concrete. It is a porous material;
whose properties depend on its different kinds of pore space. There are air
voids that are entrapped in the mixing process, the capillary pores, which are
spaces occupied by water from mixing.
Concrete
has compressible strength, which is related to the overall porosity of the
cement paste and the amount and form of the aggregates.
PRESENT STATUS
Concrete
in the present infrastructure has been deteriorating at a fast pace due to the
corrosion of reinforcing steel coming from the including chloride and other
ions from road salts, marine areas and ground soils.
Nowadays
the focus is on the transport aspect of concrete which includes diffusivity,
permeability, and absorption. Concrete is a complex composite, which needs an
improvement, monitoring and control.
The
amount of water in the mix is compared with the amount of cement is called the
water/cement ratio. The lower the water-cement ratio, the stronger is the
concrete. It has higher strength and
less permeability. The qualities expected of it are resistance to freezing and
thawing and deicing chemicals, water-tightness, low permeability, wear
resistance, and tough strength.
Admixtures
are additions to the mix which are used to achieve certain goals. When
Accelerating admixture-accelerators are added to concrete they reduce setting
time of the concrete and accelerate strength. The amount of reduction in
setting time varies. The Retarding admixtures are often used in hot weather
conditions to delay setting time. The use of Fly ash reduces the heat generated
by the concrete
Thus,
concrete is versatile and a widely used construction material, which provides
for durable, resilient and sustainable end products and serves the humanity in
a big way.
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