INTERVIEW QUESTION AND ANSWER

BUILDING MATERIALS

SECTION 1

1.
In a mortar, the binding material is
A.  Cement  B.  sand
C.  Surkhi  D.  cinder.
Answer: Option A


2.
Lacquer paints
A.  are generally applied on structural steel
B.  are less durable as compared to enamel paints
C.  consist of resin and nitro-cellulose
D.  contain alcohol as thinner
E.  all the above.
Answer: Option E


3.
Wrought iron contains carbon upto
A.  0.25%  B.  1.0%
C.  1.5%  D.  2%.

Answer: Option A


4.
Pick up the polymineralic rock from the following:
A.  Quartz sand
B.  Pure gypsum
C.  Magnesite
D.  Granite
E.  None of these.
Answer: Option D


5.
Pick up the correct statement from the following:
A.
For thin structures subjected to wetting and drying, the water cement ratio should be
0.45
B.
For mass concrete structures subjected to wetting and drying, the water ratio should be
0.55
C.
For thin structures which remain continuously under water, the water-cement ratio by
weight should be 0.55
D.
For massive concrete structures which remain continuously under water, the water
cement ratio by weight should be 0.65
E.  All the above.
Answer: Option E


6.
Ultimate strength to cement is provided by
A.  Tricalcium silicate
B.  Di-calcium silicate
C.  Tri-calcium aluminate
D.  Tetra calcium alumino ferrite.
Answer: Option B


7.
Elastomers can extend upto
A.  five times their original dimensions
B.  seven times their original dimensions
C.  ten times their original dimensions
D.  three times their original dimensions.
Answer: Option C


8.
Bitumen felt
A.  is used as water proofing material
B.  is used as damp proofing material
C.  is made from bitumen and hessian fibres
D.  all the above.
Answer: Option D


9.
In the method of condensation polymerization,
A.  low-molecular substances are removed from the high molecular substance
B.  the reaction proceeds with an evolution of ammonia
C.  the reaction proceeds with an evolution of hydrogen chloride
D.  all the above.
Answer: Option D


10.
In the cement the compound quickest to react with water, is
A.  Tricalcium aluminate
B.  Tetra-calcium alumino-ferrite
C.  Tricalcium silicate
D.  Dicalcium silicate.
Answer: Option A


11.
The initial setting time of lime-pozzolona, is
A.  30 minutes
B.  60 minutes
C.  90 minutes
D.  120 minutes.
Answer: Option D


12.
The clay to be used for manufacturing bricks for a large project, is dugout and allowed to weather
throughout
A.  the monsoon
B.  the winter
C.  the summer
D.  none of these.
Answer: Option A


13.
The rocks which are formed due to cooling of magma at a considerable depth from earth's surface
are called
A.  Plutonic rocks
B.  Hypabyssal rocks
C.  Volcanic rocks
D.  Igneous rocks.
Answer: Option A


14.
Quartzite is a
A.  metamorphic rock
B.  argillaceous rock
C.  calcareous rock
D.  silicious rock.
Answer: Option D


15.
The variety of pig iron used for manufacture of wrought iron, is
A.  Bessemer pig
B.  Grey or foundry pig
C.  White forge pig
D.  Mottled pig.
Answer: Option C


16.
Sand stone is
A.  sedimentary rock
B.  metamorphic rock
C.  igneous rock
D.  volcanic rock.
Answer: Option A


17.
If the furnace is provided with insufficient fuel at low temperatures, the type of pig iron produced,
is called
A.  Bessemer pig
B.  Grey or foundry pig
C.  White or forge pig
D.  Mottled pig.
 Answer: Option C


18.
Stainless steel contains
A.  18% of chromuim and 8% nickel
B.  8% of chromium and 18% of nickel
C.  12% of chromium and 36% of nickel
D.  36% of chromium and 12% of nickel.
Answer: Option A


19.
Pick up the hypabyssal rock from the following:
A.  Granite
B.  Dolerite
C.  Basalt
D.  All the above.
Answer: Option B


20.
Depending on the chemical composition and mechanical properties, iron may be classified as
A.  cast iron
B.  wrought iron
C.  Steel
D.  all the above.
Answer: Option B


21.
Wrought iron contains carbon about
A.  1.5% to 5.5%
B.  0.5% to 1.75%
C.  0.1% to 0.25%
D.  none to these.
Answer: Option C


22.
The main constituent of fly-ash, is
A.  aluminium oxide
B.  Silica
C.  ferrous oxide
D.  All of these.
Answer: Option D


23.
Bitumen in
A.  solid state, is called asphalt
B.  semi fluid state, is called mineral tar
C.  fluid state, is called petroleum
D.  all the above.
Answer: Option D


24.
The plastics made from cellulose resin
A.  are as clear as glass
B.  are tough and strong
C.  possess excellent electrical properties
D.  All the above.
Answer: Option D


25.
Kaolin is chemically classified as
A.  metamorphic rock
B.  argillaceous rock
C.  calcareous rock
D.  silicious rock.
Answer: Option B


26.
Which one of the following is acid resistant asbestos:
A.  actinolite asbestos
B.  amosite asbestos
C.  anthophylite asbestos
D.  crocidolite asbestos
E.  All the above.
Answer: Option E


27.
Due to attack of dry rot, the timber
A.  Cracks
B.  Shrinks
C.  reduces to powder
D.  none of these.
Answer: Option C


28.
Brittleness of cold is due to an excess of
A.  Sulphur  B.  Carbon
C.  phosphorus  D.  silicon.
Answer: Option C


29.
For the manufacture of Portland cement, the proportions of raw materials used, are
A.  lime 63% ; silica 22% ; other ingredients 15%
B.  lime 22% ; silica 63% ; other ingredients 15%
C.  silica 40% ; lime 40% ; other ingredients 20%
D.  silica 70% ; lime 20% ; other ingredients 10%.
Answer: Option A


30.
Asbestos cement
A.  is brittle
B.  warps due to changes in humidity
C.  strength is lowered when saturated by water
D.  all the above.
Answer: Option D


31.  Gniess is obtained from
A.  igneous rocks
B.  metamorphic rocks
C.  sedimentary rocks
D.  sedimentary metamorphic rocks.
Answer: Option D


32.
The rocks formed by gradual deposition, are called
A.  sedimentary rocks
B.  igneous rocks
C.  metamorphic rocks
D.  none of these.
Answer: Option A


33.
Galvanising means covering iron with a thin coat of
A.  Tin
B.  Zinc
C.  Glaze
D.  coal tar.
Answer: Option B


34.
For preparing porcelains, the clay should be
A.  sufficiently pure
B.  of high degree of tanacity
C.  of good plasticity
D.  All the above.
Answer: Option D


35.
Polymerization helps to improve the property of
A.  Strength
B.  Rigidity
C.  Elasticity
D.  all of these.
Answer: Option D


36.
Good quality stones must
A.  be durable
B.  be free from clay
C.  resist action of acids
D.  all the above.
Answer: Option D


37.
Sewer pipes are made of
A.  earthen ware
B.  stone ware
C.  refractory clay
D.  Terracotta
E.  all the above.
Answer: Option B


38.
Fibre glass
A.  retains heat-longer
B.  has a higher strength to weight ratio
C.  is shock proof and fire retardent
D.  does not decay
E.  all the above.
Answer: Option E


39.
Pick up the correct statement from the following:
A.
The theory of formation of concrete is based on the phenomena of formation of
voids
B.
The bulking of sand is taken into account while volumetric proportioning of the
aggregates
C.
The dry sand and the sand completely flooded with water, have practically the
same volume
D.
The expansion and contraction joints are provided if concrete structures exceed
12 m in length
E.  All the above.
Answer: Option E


40.
Pick up the correct statement from the following:
A.  In stone arches, the stones are placed with their natural beds radial
B.  In cornices, the stones are placed with their natural beds as vertical
C.  In stone walls, the stones are placed with their natural beds as horizontal
D.  All the above.
Answer: Option D


41.
The commonly used colour pigment in paints, is
A.  Ambers
B.  carbon black
C.  iron oxide
D.  lamp black
E.  all the above.
Answer: Option E


42.
Varnish is a transparent or semi-transparent solution of resinuous substances in
A.  Alcohol
B.  Linseed
C.  Turpentine
D.  all the above.
Answer: Option D


43.
Initial setting time of cement for asbestos cement products should be not less than
A.  30 minutes
B.  50 minutes
C.  75 minutes
D.  90 minutes.
Answer: Option D


44.
The variety of pig iron used for the manufacture of steel by Bessemer process, is
A.  Bessemer pig
B.  Grey pig
C.  White forge pig
D.  Mottled pig.
Answer: Option A


45.
For melting one tonne of cast iron
A.  700 m^3 air is required
B.  20 kg limestone is required
C.  one quintal coke is required
D.  all the above.
Answer: Option D


46.
For filling cracks in masonry structures, the type of bitumen used, is
A.  cut-back bitumen
B.  bitumen-emulsion
C.  blown bitumen
D.  plastic bitumen.
Answer: Option D


47.
Plastic
A.  is an organic substance
B.  consists of natural or synthetic binders
C.  finished products are rigid and stable at normal temperature
D.  is capable of flow when necessary heat and pressure are applied
E.  All the above.
Answer: Option E


48.
Vanadium steel is generally used for
A.  railway switches and crossing
B.  bearing balls
C.  Magnets
D.  axles and springs.
Answer: Option D


49.
Pick up the correct statement from the following:
A.  In basic Bessemer process, the steel heats the converter
B.  In open-hearth process, the furnace heats the steel
C.
In Siemens process, the impurities of pig iron are oxidised by the
oxygen of the ore
D.  all the above.
Answer: Option D


50.
The process of manufacturing steel by heating short lengths of wrought iron bars
mixed with charcoal in fire clay crucibles and collecting the molten iron into
moulds, is known as
A.  Cementation process
B.  Crucible process
C.  Bessemer process
D.  Open hearth process.
Answer: Option B

   

What are the steps involved in the concreting process, explain?

The major steps involved in the process of concreting are as follows:
1. Batching
2. Mixing
3. Transporting and placing of concrete
4. 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.

Describe briefly the various methods of concrete curing.

Curing is the process of maintaining the moisture and temperature conditions for freshly deployed concrete. This is done for small duration of time to allow the hardening of concrete. The methods that are involved in saving the shrinkage of the concrete includes:
(a) Spraying of water: on walls, and columns can be cured by sprinkling water.
(b) Wet covering of surface: can be cured by using the surface with wet gunny bags or straw
(c) Ponding: the horizontal surfaces including the slab and floors can be cured by stagnating the water.
(d) Steam curing: of pre-fabricated concrete units steam can be cured by passing it over the units that are under closed chambers. It allows faster curing process and results in faster recovery.
(e) Application of curing compounds: compounds having calcium chloride can be applied on curing surface. This keeps the surface wet for a very long time.

What do you understand by “preset” during the installation process of bridge bearings?

During the installation of bridge bearings the size of the upper plates is reduced to save the material costs. This process is known as preset.
Generally the upper bearing plate comprises of the following components:
> Length of bearing
> 2 x irreversible movement.
> 2 x reversible movement.
The bearing initially is placed right in the middle point of the upper bearing plate. No directional effects of irreversible movement is considered. But since the irreversible movement usually takes place in one direction only the displaced direction is placed away from the midpoint. In such cases the length of the upper plate is equal to the length of the length of the bearing + irreversible movement + 2 x reversible movement.

Why are steel plates inserted inside bearings in elastomeric bearings?

In order to make a elastomeric bearing act/ function as a soft spring it should be made to allow it to bulge laterally and also the stiffness compression can be increased by simply increasing the limiting amount of the lateral bulging. In many cases in order to increase the compression stiffness of the bearing the usage of metal plates is made. Once steel plates are included in the bearings the freedom of the bulge is restricted dramatically, also the deflection of the bearing is reduced as compared to a bearing without the presence of steel plates. The tensile stresses of the bearings are induced into the steel plates. But the presence of the metal plates does not affect the shear stiffness of the bearings.

What reinforcements are used in the process of prestressing?

The major types of reinforcements used in prestressing are:
> 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.