Concrete Technology MCQs Set-2

Page 1 of 4

1. The admixtures are added in concrete to

make the concrete water proof, acid proof etc.

accelerate the rate of setting and hardening of cement

all of these

reduce the bleeding and segregation of concrete mix

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

greater than 2

between 1 and 1.5

less than 1

between 1.5 and 2

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

cylinder

none of these

cube

frustum of a cone

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

all of these

filler

catalyst

binding material

5. Reinforced cement concrete is equally strong in taking

compressive and shear stresses

tensile, compressive and shear stresses

tensile and compressive stresses

tensile and shear stresses

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

0.33

1.0

0.75

0.5

7. 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), (ii) and (iii)

(i) and (ii)

(ii) and (iii)

(i) and (iii)

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

decreasing the setting time by about 1 hour

decreasing the setting time by about 4 hour

increasing the setting time by about 1 hour

increasing the setting time by about 4 hour

9. Lime when added in excess quantity

(d) both (a) and (b)

(a) makes the cement unsound

(c) lowers the clinkering temperature of cement

(b) causes the cement to expand and disintegrate

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

rapid hardening cement

high alumina cement

low heat cement

sulphate resisting cement

Page 2 of 4

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

slump test

works test

preliminary test

none of these

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

100mm, 200mm, 300mm

200mm, 300mm, 100mm

200mm, 100mm, 300mm

100mm, 300mm, 200mm

13. Rapid hardening cement is used

for constructing road pavements

where form work is to be removed as early as possible

where high early strength is desired

all of these

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

mm/h

minutes

mm²/h

mm

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

coke breeze

all of these

furnace clinker

saw dust

16. A higher modular ratio shows

lower compressive strength of concrete

lower tensile strength of steel

higher compressive strength of concrete

higher tensile strength of steel

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

all of these

chalk

shells

lime stone

18. The percentage of voids in cement is approximately

40%

60%

25%

80%

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

14 days

7 days

28 days

3 days

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

directly proportional to square root of compressive strength

directly proportional to compressive strength

inversely proportional to square root of compressive strength

inversely proportional to compressive strength

Page 3 of 4

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

clay

silt

none of these

sand

22. The aggregate is said to be flaky when

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

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

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

2 times the least lateral dimension

3 times the least lateral dimension

4 times the least lateral dimension

the least lateral dimension

24. The maximum particle size of coarse aggregate is

65 mm

45 mm

75 mm

55 mm

25. In lime concrete, lime is used as

fine aggregate

admixture

binding material

coarse aggregate

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

d) none of these

a) volume batching only

c) both (a) and (b)

b) weight batching only

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

350 kg

450 kg

200 kg

100 kg

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

lime

iron oxide

silica

alumina

29. The maximum particle size of fine aggregate is

4.75 mm

6.5 mm

2.5 mm

5.85 mm

30. The type of lime used in lime concrete is

slaked lime

fat lime

hydraulic lime

poor lime

Page 4 of 4

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

specific gravity of the aggregate

shape of the aggregate

grading of the aggregate

average size of particles in the aggregate

32. Normally, when ordinary Portland cement hydrates

cement paste cools down below atmospheric temperature

heat neither evolves nor is absorbed

heat evolves

heat is absorbed

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

all in aggregate

coarse aggregate

cyclopean aggregate

fine aggregate

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

Silica

Alumina

Lime

Iron oxide

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

0.70

0.50

0.65

0.60

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

all of these

mobility

consistency

homogeneity

37. Modulus of rupture of concrete is a measure of

flexural tensile strength

direct tensile strength

split tensile strength

compressive strength

38. Curing period required is minimum for the concrete using

rapid hardening cement

portland slag cement

low heat portland cement

ordinary portland cement

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

low

high

medium

very low

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

none of these

rapid hardening

high heat generation

high early strength

Concrete Technology MCQs Set-2

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