Q.1

Concrete gains strength due to

  • chemical reaction of cement with sand and coarse aggregates
  • evaporation of water from concrete
  • hydration of cement
  • All the above.
Q.2

Pick up the incorrect statement from the following:

  • In properly graded aggregates, bulk density is more
  • In single size aggregates, bulk density is least
  • In single size aggregates, bulk density is maximum
  • None of these.
Q.3

Concrete is unsuitable for compaction by a vibrator if it is

  • dry
  • earth moist
  • semi-plastic
  • plastic
  • none of these.
Q.4

The diameter of the Vicat plunger ismm and its length varies from

  • 20 mm to 30 mm
  • 30 mm to 40 mm
  • 40 mm to 50 mm
  • 50 mm to 60 mm
  • none of these.
Q.5

The commercial name of white and coloured cement in India, is

  • colocrete
  • rainbow cement
  • silvicrete
  • snowcem
  • all the above.
Q.6

The grade of concrete Mmeans that compressive strength of acm cube afterdays, is

  • 100 kg/cm2
  • 150 kg/cm2
  • 200 kg/cm2
  • 250 kg/cm2
  • 300 kg/cm2
Q.7

The type of aggregates of same nominal size, which contain less voids when compacted, are

  • rounded spherical
  • irregular
  • flaky
  • none of these.
Q.8

Construction joints are provided

  • where B.M. and S.F. are small
  • where the member is supported by other member
  • at 18 m apart in huge structures
  • in concrete wall at sill level of windows
  • all the above.
Q.9

The cement whose strength is a little lower than the ordinary cement during the first three months but attains afterwards the same strength, is known as

  • low-heat Portland cement
  • rapid hardening Portland cement
  • Portland blast slag cement
  • Portland pozzolana cement
  • none of these.
Q.10

The condition not applicable to water cement ratio law, is

  • internal moisture conditions on hydration continue till complete strength is gained
  • concrete specimens may be tested at any temperature
  • concrete specimens need be of same age
  • concrete specimens need be of same size
  • none of these.
Q.11

Transport of concrete by pumps, is done for a distance of

  • 100 m
  • 200 m
  • 300 m
  • 400 m
  • none of these.
Q.12

The type of aggregates of same nominal size, which contain less voids when compacted, are

  • rounded spherical
  • irregular
  • flaky
  • none of these.
Q.13

The top diameter, bottom diameter and the height of a slump mould are :

  • 10 cm, 20 cm, 30 cm
  • 10 cm, 30 cm, 20 cm
  • 20 cm, 10 cm, 30 cm
  • 20 cm, 30 cm, 10 cm
  • 30 cm, 20 cm, 10 cm
Q.14

Slump test of concrete is a measure ofits

  • consistency
  • compressive strength
  • tensile strength
  • impact value.
Q.15

If aggregates completely pass through a sieve of sizemm and are retained on a sieve of sizemm, the particular aggregate will be flaky if its minimum dimension is less than

  • 20.5 mm
  • 30.5 mm
  • 40.5 mm
  • 50.5 mm
  • none of these.
Q.16

Mgrade of concrete approximates

  • 1 : 3 : 6 mix
  • 1 : 1 : 2 mix
  • 1 : 2 : 4 mix
  • 1 : 1.5 : 3 mix
  • none of these.
Q.17

For the construction of cement concrete floor, the maximum permissible size of aggregate, is

  • 4 mm
  • 6 mm
  • 8 mm
  • 10 mm
  • 12 mm
Q.18

Concrete mainly consists of

  • cement
  • aggregates
  • admixture
  • water
  • all the above.
Q.19

To ensure constant moisture content in aggregates

  • area of each aggregate pile should be large
  • height of each aggregate pile should not exceed 1.50 m
  • aggregate pile should be left for 24 hours before aggregates are used
  • conical heaps of aggregates should be avoided to prevent moisture variation
  • all the above.
Q.20

Saw dust can be rendered chemically inert by boiling it in water containing

  • ferrous sulphate
  • potassium chloride
  • ammonia
  • nitric acid
  • sulphuric acid.
Q.21

Inert material of a cement concrete mix, is

  • water
  • cement
  • aggregate
  • none of these.
Q.22

The shrinkage of concrete

  • is proportional to water content is the mix
  • is proportional to cement concrete
  • increases with age of concrete
  • all the above.
Q.23

Pick up the correct statement from the following:

  • An increase in water content must be accompanied by an increase in cement content
  • Angular and rough aggregates reduce the workability of the concrete
  • Large size aggregates increase the workability due to lesser surface area
  • The slump of the concrete mix decreases due to an increase in temperature
  • All the above.
Q.24

Allowable shear strength of concrete, depends upon

  • shear strength
  • tensile strength
  • compressive strength
  • none of these.
Q.25

For the construction of cement con-certe dams, the maximum permissible size of the aggregates, is

  • 40 mm
  • 50 mm
  • 60 mm
  • 70 mm
  • 80 mm
Q.26

An aggregate is said to be flaky if its least dimension is less than

  • 1/5th of mean dimension
  • 2/5th of mean dimension
  • 3/5th of mean dimension
  • 4/5th of mean dimension
  • none of these.
Q.27

Pick up the correct statement from the following:

  • Sand stones may be divided into calcareous, siliceous and ferrugineous sand stones
  • Concrete using sand stones, cracks due to excessive shrinkage
  • Very hard and close grained crystallined lime stones are suitable aggregates but provide low strength
  • Broken bricks produce a concrete having good fire resisting qualities
  • All the above.
Q.28

High temperature

  • increases the strength of concrete
  • decreases the strength of concrete
  • has no effect on the strength of concrete
  • none of these.
Q.29

Workability of concrete mix with low water cement ratio is determined by

  • tensile strength test
  • slump test
  • compaction factor test
  • flexural strength test
  • none of these.
Q.30

The maximum amount of dust which may be permitted in aggregates is

  • 5% of the total aggregates for low workability with a coarse grading
  • 10% of the total aggregates for low workability with a fine grading
  • 20% of the total aggregates for a mix having high workability with fine grading
  • all the above.
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