Concrete Technology MCQs Set-2

Page 1 of 4

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

very low

low

medium

high

2. 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

0.60

0.65

3. Reinforced cement concrete is equally strong in taking

tensile, compressive and shear stresses

compressive and shear stresses

tensile and compressive stresses

tensile and shear stresses

4. The percentage of voids in cement is approximately

60%

80%

25%

40%

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

none of these

clay

silt

sand

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 maximum particle size of fine aggregate is

4.75 mm

2.5 mm

5.85 mm

6.5 mm

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

works test

preliminary test

none of these

slump test

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

100mm, 200mm, 300mm

100mm, 300mm, 200mm

200mm, 100mm, 300mm

200mm, 300mm, 100mm

10. 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

(ii) and (iii)

(i) and (ii)

(i), (ii) and (iii)

(i) and (iii)

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

average size of particles in the aggregate

shape of the aggregate

grading of the aggregate

specific gravity of the aggregate

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

coarse aggregate

all in aggregate

fine aggregate

cyclopean aggregate

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

Lime

Silica

Iron oxide

Alumina

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

between 1.5 and 2

less than 1

between 1 and 1.5

greater than 2

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

rapid hardening

high heat generation

none of these

high early strength

16. Modulus of rupture of concrete is a measure of

direct tensile strength

split tensile strength

flexural tensile strength

compressive strength

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

lime

iron oxide

silica

alumina

18. The aggregate is said to be flaky when

its length is equal to its mean dimension

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

its least dimension is equal to its mean dimension

its length is equal to 1.8 times its mean dimension

19. In lime concrete, lime is used as

admixture

fine aggregate

coarse aggregate

binding material

20. Lime when added in excess quantity

(a) makes the cement unsound

(c) lowers the clinkering temperature of cement

(d) both (a) and (b)

(b) causes the cement to expand and disintegrate

Page 3 of 4

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

low heat cement

rapid hardening cement

sulphate resisting cement

high alumina cement

22. The type of lime used in lime concrete is

hydraulic lime

poor lime

slaked lime

fat lime

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

450 kg

350 kg

200 kg

100 kg

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

decreasing the setting time by about 1 hour

increasing the setting time by about 4 hour

increasing the setting time by about 1 hour

decreasing the setting time by about 4 hour

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

4 times the least lateral dimension

the least lateral dimension

3 times the least lateral dimension

2 times the least lateral dimension

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

mm

mm/h

mm²/h

minutes

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

directly proportional to compressive strength

directly proportional to square root of compressive strength

inversely proportional to compressive strength

inversely proportional to square root of compressive strength

28. Curing period required is minimum for the concrete using

ordinary portland cement

rapid hardening cement

portland slag cement

low heat portland cement

29. The maximum particle size of coarse aggregate is

45 mm

55 mm

75 mm

65 mm

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

cube

none of these

frustum of a cone

cylinder

Page 4 of 4

31. 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

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

lime stone

all of these

chalk

shells

33. Rapid hardening cement is used

where high early strength is desired

where form work is to be removed as early as possible

all of these

for constructing road pavements

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

consistency

homogeneity

mobility

all of these

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

7 days

28 days

3 days

14 days

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

a) volume batching only

d) none of these

c) both (a) and (b)

b) weight batching only

37. Normally, when ordinary Portland cement hydrates

cement paste cools down below atmospheric temperature

heat neither evolves nor is absorbed

heat evolves

heat is absorbed

38. The admixtures are added in concrete to

all of these

make the concrete water proof, acid proof etc.

reduce the bleeding and segregation of concrete mix

accelerate the rate of setting and hardening of cement

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

coke breeze

all of these

saw dust

furnace clinker

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

filler

binding material

catalyst

all of these

Concrete Technology MCQs Set-2

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