6. Define Reinforcement?
Ans:
Reinforced concrete is a
composite material in which concrete's relatively low tensile strength and
ductility are counteracted by the inclusion of reinforcement having higher
tensile strength and/or ductility that a strong reason of today most of
engineers are use reinforced concrete.
7. What are the steps involved in the concreting process, explain?
Ans:
The major steps involved in the
process of concreting are as follows:
a. Batching
b. Mixing
c. Transporting and placing of
concrete
d. Compacting.
Batching: The process of
measurement of the different materials for the making of concrete is known as
batching. batching is usually done in two ways: volume batching and weight batching.
In case of volume batching the measurement is done in the form of volume
whereas in the case of weight batching it is done by the weight.
Mixing: In order to create good
concrete the mixing of the materials should be first done in dry condition and
after it wet condition. The two general methods of mixing are: hand mixing and
machine mixing.
Transportation and placing of
concrete: Once the concrete mixture is created it must be transported to its
final location. The concrete is placed on form works and should always be
dropped on its final location as closely as possible.
Compaction of concrete: When
concrete is placed it can have air bubbles entrapped in it which can lead to
the reduction of the strength by 30%. In order to reduce the air bubbles the
process of compaction is performed. Compaction is generally performed in two
ways: by hand or by the use of vibrators.
8. What reinforcements are used in the process of prestressing?
Ans:
Spalling Reinforcement: The
spalling stresses leads to stress behind the loaded area of the anchor blocks.
This results in the breaking off of the surface concrete. The most likely
causes of such types of stresses are Poisson`s effects strain interoperability
or by the stress trajectory shapes.
Equilibrium reinforcements: This
type of reinforcements are required where several anchorages exist where the
prestressing loads are applied in a sequential manner.
Bursting Reinforcements: These
kinds of stresses occur in cases where the stress trajectories are concave towards
the line of action of load. In order to reduce such stresses reinforcements in
the form of bursting is required.
9. What are the causes of building collapse?
Ans:
The Passage of time is one
reason. Buildings also collapse due to weak foundations. Earthquakes,
hurricanes and other natural disasters can also damage the structure of the
buildings and cause it to collapse. Bombings or demolition of buildings is also
other reasons.
10. How do you measure concrete?
Ans:
Cubic feet, Cubic yards, Cubic
Meter
11. What are the applications of modulus of elasticity?
Ans:
As the term implies, “Modulus of
Elasticity relates to the elasticity or “flexibility” of a material. The value
of modulus of elasticity is very much significant relating to deflection of
certain materials used in the construction industry. Take for example the
general E value of mild carbon steel is about 200 GPA compared to about 70 GPA
for aluminum. This simply translate that aluminum is 3 times flexible than
steel.
12. What is the meaning of soil reinforcement?
Ans:
Soil reinforcement is the act of
improving soil strength to enable it support or carry more load. Two common
examples are: a) Mixing a soil amendment such as lime into weak clayey soil and
re-compacting to improve soil- bearing capacity (often done under the road base
in highway construction) b) Installing plastic or composite webbing layers
(called geogrid material) alternating with compacted soil to produce a stronger
sloped soil structure (often done on steep roadway embankments to improve
strength and stability).
13. What is Stress?
Ans:
In engineering, Stress is an
external force that pushes, pulls, twists, or otherwise puts force on something.
Engineering stress assumes that the area a force is acting upon remains
constant, true stress takes into account the reduction in area caused by the
force.
14. What are moment of inertia and its importance in civil engineering?
Ans:
The moment of inertia measures
the opposition any kind of body will have against a certain momentum (along
that same axis) trying to rotate that body.
15. How long does it take concrete to harden?
Ans:
It takes 28 days to cure.
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