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
Cementation process
Crucible process
Bessemer process
Open hearth process
Correct Answer :
B. Crucible process
Related Questions
Spalling hammer is used for
Driving wooden headed chisels
Rough dressing of stones
Carving of stones
Breaking small projection of stones
The pigment used in paints for corrosive resistance, is
White lead
Ferrous oxide
Zinc white
Red lead
Portland pozzolana cement possesses
Higher resistance to chemical attack
Lower heat of hydration
Lower shrinkage on drying
All the above
Quick lime is
Calcium carbonate
Calcium oxide
Calcium hydroxide
None of the above
The main constituent which imparts hydraulicity to hydraulic lime is
Calcium oxide
Silica
Clay
Water
For construction of structures under water, the type of lime used, is
Hydraulic lime
Fat lime
Quick lime
Pure lime
Pick up the correct characteristic of Pyroxene from the following:
It forms octagonal crystals
It converts to chlorine by hydration
Its density is 2.3 to 3.6 g/cm2
All the above
Bitumen emulsion is
A liquid containing bitumen in suspension
A paint
Used as anti-corrosive paint
All the above
Pick up the correct statement from the following:
Blistering may be cured by applying water paint finished with oil paint dried with a little copal varnish
Cracked paints may be cured by removing paint and giving a fresh coat of paint
Crawling paints may be cured by sand preparing the surface and giving a fresh coat with plenty of turps
All the above
The constituent of cement which is responsible for all the undesirable properties of cement is
Di-calcium silicate
Tri-calcium silicate
Tri-calcium aluminate
Tetra calcium alumino ferrite
The standard size of masonry bricks, is
18 cm × 8 cm × 8 cm
19 cm × 9 cm × 9 cm
20 cm × 10 cm × 10 cm
21 cm × 11 cm × 11 cm
Pick up the correct statement from the following:
The theory of formation of concrete is based on the phenomena of formation of voids
The bulking of sand is taken into account while volumetric proportioning of the aggregates
The dry sand and the sand completely flooded with water, have practically the same volume
All the above
Mastic asphalt is
Acid resisting material
Non-corrosive material
Corrosive material
Heating-resisting material
The percentage of alumina and silica in good fire clay vary respectively is
25, 75
30, 70
35, 65
All of these
Asbestos
Is a natural fibrous mineral substance
Is composed of hydrous silicates of calcium and magnesium (CaSiO3, 3MgSiO3)
Contains iron oxide and alumina
All the above
The thermosetting plastic
Becomes rigid when moulded at suitable pressure and temperature
At 127°C to 177°C permanently set and further application of heat does not soften it
Chars at 343°C
All the above
Initial setting time of cement for asbestos cement products should be not less than
30 minutes
50 minutes
75 minutes
90 minutes
A rock contains only one mineral. It is called
Homogeneous
Non-homogeneous
Monomineralic
Polymineralic
The hardest rock is
Marble
Diamond
Talc
Quartz
Pick up the correct statement regarding low heat cement from the following:
It possesses less compressive strength
Its initial setting time is about one hour
Its final setting time is about 10 hours
All the above
Which of the following trees yields hard wood?
Deodar
Chir
Shishum
Pine
Asphalt is obtained from
Petroleum distillation
Bitumen distillation
Plastic distillation
None of these
Spirit varnish generally consists of
Oil, wax and resin
Alcohol, wax and turpentine
Pigment and synthetic resin
Spirit and shellac
Oil varnish generally consists of
Synthetic resin and spirit
Oil, wax and resin
Resin, oil and turpentine
Spirit, oil and wax
Proper amount of entrained air in concrete results in (i) Better workability (ii) Better resistance to freezing and thawing (iii) Lesser workability (iv) Less resistance to freezing and thawing The correct answer is
(i) and (ii)
(i) and (iv)
(ii) and (iii)
(iii) and (iv)
For sanitary pipes and chemical stonewares,
Salt glazing is used
Lead glazing is used
Opaque glazing is used
None of these
In the cement the compound quickest to react with water, is
Tri-calcium aluminate
Tetra-calcium alumino-ferrite
Tri-calcium silicate
Di-calcium silicate
Pick up the rock which is not a sedimentary rock from the following:
Gravel
Sand stone
Gypsum
Dolerite
Wrought iron contains carbon about
1.5% to 5.5%
0.5% to 1.75%
0.1% to 0.25%
None to these
Stucco paints are suitable for
Stone masonry
Brick walls
Both (A) and (B)
Neither (A) nor (B)