Concrete Technology MCQs Set-2

Page 1 of 4

1. The percentage of voids in cement is approximately

25%

80%

60%

40%

2. According to IS:456-1978, the flexural strength of concrete is

directly proportional to square root of compressive strength

inversely proportional to compressive strength

inversely proportional to square root of compressive strength

directly proportional to compressive strength

3. Lime when added in excess quantity

(c) lowers the clinkering temperature of cement

(a) makes the cement unsound

(d) both (a) and (b)

(b) causes the cement to expand and disintegrate

4. According to IS: 456-1978, the maximum water-cement ratio in plain concrete to ensure durability in mild exposure is limited to

0.50

0.70

0.65

0.60

5. The fineness modulus of an aggregate is roughly proportional to

specific gravity of the aggregate

average size of particles in the aggregate

grading of the aggregate

shape of the aggregate

6. According to IS: 456-1978, the column or the strut is the member whose effective length is greater than

the least lateral dimension

4 times the least lateral dimension

2 times the least lateral dimension

3 times the least lateral dimension

7. The admixtures are added in concrete to

make the concrete water proof, acid proof etc.

all of these

accelerate the rate of setting and hardening of cement

reduce the bleeding and segregation of concrete mix

8. The presence of entrained air in concrete results in

i) reducing bleeding

ii) lowering density of concrete

iii) decreasing strength at all ages

The correct answer is

(i) and (iii)

(i) and (ii)

(i), (ii) and (iii)

(ii) and (iii)

9. The approximate value of the ratio between direct tensile strength and flexural strength is

0.5

1.0

0.33

0.75

10. The aggregate which pass through 4.75 mm IS sieve and entirely retain on 75 micron IS sieve is called

coarse aggregate

cyclopean aggregate

all in aggregate

fine aggregate

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11. Low percentage of tricalcium silicate and high percentage of dicalcium silicate in cement result in

none of these

high early strength

rapid hardening

high heat generation

12. The workability of concrete by slump test is expressed as

minutes

mm

mm²/h

mm/h

13. Which of the following ingredient of cement when added in excess quantity, causes the cement to set slowly?

Lime

Iron oxide

Alumina

Silica

14. The slump test of concrete is used to measure its

mobility

all of these

homogeneity

consistency

15. If the slump of concrete mix is 70mm, its workability is considered to be

low

very low

high

medium

16. Curing period required is minimum for the concrete using

rapid hardening cement

portland slag cement

ordinary portland cement

low heat portland cement

17. Calcareous material used in the manufacture of cement consist of

shells

all of these

lime stone

chalk

18. The test conducted in the laboratory on the specimen made out of trial concrete mix is called

none of these

works test

slump test

preliminary test

19. Reinforced cement concrete is equally strong in taking

compressive and shear stresses

tensile and compressive stresses

tensile, compressive and shear stresses

tensile and shear stresses

20. The chemical ingredient of cement which provides quick setting property to the cement is

alumina

lime

iron oxide

silica

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21. The maximum particle size of coarse aggregate is

75 mm

65 mm

55 mm

45 mm

22. The maximum particle size of fine aggregate is

2.5 mm

5.85 mm

6.5 mm

4.75 mm

23. The steel mold used for slump test is in the form of a

cylinder

cube

none of these

frustum of a cone

24. In concrete mix design, allowance for bulking of sand is necessary in case of

d) none of these

a) volume batching only

b) weight batching only

c) both (a) and (b)

25. In lime concrete, lime is used as

coarse aggregate

fine aggregate

admixture

binding material

26. For the manufacture of concrete of low density, the aggregate used is

furnace clinker

saw dust

all of these

coke breeze

27. Rapid hardening cement is used

all of these

for constructing road pavements

where high early strength is desired

where form work is to be removed as early as possible

28. According to IS: 456-1978, minimum period stipulated for moist curing of concrete using ordinary Portland cement is

28 days

7 days

14 days

3 days

29. The aggregate is said to be flaky when

its length is equal to its mean dimension

its length is equal to 1.8 times its mean dimension

its least dimension is equal to its mean dimension

its least dimension is less than three-fifth of its mean dimension

30. The material having particle size varying from 0.002 to 0.06 mm is termed as

none of these

silt

sand

clay

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31. The function of aggregates in concrete is to serve as

all of these

catalyst

binding material

filler

32. A higher modular ratio shows

lower tensile strength of steel

higher tensile strength of steel

lower compressive strength of concrete

higher compressive strength of concrete

33. The maximum quantity of aggregate per 50kg of cement should not exceed

200 kg

100 kg

450 kg

350 kg

34. Normally, when ordinary Portland cement hydrates

heat neither evolves nor is absorbed

heat evolves

cement paste cools down below atmospheric temperature

heat is absorbed

35. Modulus of rupture of concrete is a measure of

flexural tensile strength

compressive strength

direct tensile strength

split tensile strength

36. The top diameter, bottom diameter and height of the mould used for slump test are respectively

100mm, 300mm, 200mm

200mm, 300mm, 100mm

200mm, 100mm, 300mm

100mm, 200mm, 300mm

37. For a structure subjected to the action of sea water, the cement used is

rapid hardening cement

sulphate resisting cement

high alumina cement

low heat cement

38. Addition of sugar in concrete (about 0.05% of weight of cement) results in

increasing the setting time by about 4 hour

decreasing the setting time by about 1 hour

decreasing the setting time by about 4 hour

increasing the setting time by about 1 hour

39. The type of lime used in lime concrete is

hydraulic lime

slaked lime

fat lime

poor lime

40. The slab is designed as one way if the ratio of long span to short span is

between 1.5 and 2

greater than 2

between 1 and 1.5

less than 1

Concrete Technology MCQs Set-2

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