Civil Engineering - Concrete Technology MCQs Part 2

1. Separation of coarse aggregates from mortar during transportation, is known

A.
bleeding

B.
creeping

C.
segregation

D.
shrinkage

E.
none of these.

 Answer Option C

2. According to the recommendations of IS : 456-1978, the expansion joints

A.
are provided where plane changes abruptly

B.
are provided to ensure minimum resistance

C.
are supported on separate columns

D.
do not carry reinforcement across them

E.
all the above.

 Answer Option E

3. Grading of sand causes great variation in

A.
workability of concrete

B.
strength of concrete

C.
durability of concrete

D.
handing and placing of concrete

E.
all the above.

 Answer Option E

4. Shrinkage in concrete can be reduced by using

A.
low water cement ratio

B.
less cement in the concrete

C.
proper concrete mix

D.
presaturated aggregates

E.
all the above.

 Answer Option E

5. Ordinary concrete is not used for concrete grade

A.
M 100

B.
M 150

C.
M 200

D.
M 250

E.
M 400

 Answer Option E

6. 1.S. Sieve Nos. 10 mm and 4.75 mm are geneally used for grading of

A. coarse aggregates

B. fine aggregates

C. neither (a) nor (b)

D. both (a) and (b)

E. none of these.

 Answer Option D

7. Pick up the correct statement from the following:

A. The free water is the amount of water added while mixing and the amount of water held on the surface of the aggregates prior to mixing

B. The total water is the free water and the amount actually absorbed by the aggregates

C. Neither (a) nor (b)

D. Both (a) and (b).

 Answer Option D

8. Addition of pozzolana to ordinary port land cement, causes

A. decrease in early strength

B. reduction in chemical action with sulphates

C. increase in shrinkage

D. reduction bleeding

E. all the above.

 Answer Option E

9. Too wet concrete may cause

A. weakness of concrete

B. excessive laitance

C. segregation

D. lower density

E. all the above.

 Answer Option E

10. Addition of pozzolana to cement causes

A. reduction in permeability

B. loss of heat of hydration

C. reduction in bleeding

D. increase in curing time

E. all the above.

 Answer Option E

11. Hardening of cement occurs at

A. rapid rate during the first few days and afterwards it continues to increase at a decreased rate

B. slow rate during the first few days and afterwards it continues to increase at a rapid rate

C. uniform rate throughout its age

D. none of these.

 Answer Option D

12. Pick up the correct statement from the following:

A. Lime in excess, causes the cement to expand and disintegrate

B. Silica in excess, causes the cement to set slowly

C. Alumina in excess, reduces the strength of the cement

D. Magnesium oxide in excess, remains in free state and makes the cement unsound

E. All the above.

 Answer Option E

13. Batching error means inaccuracy in the quantity of

A. aggregates

B. cement

C. water

D. all the above.

 Answer Option D

14. Pick up the correct statement from the following i.

A. Higher workability indicates unexpected increase in the moisture content

B. Higher workability indicates deficiency of sand

C. If the concrete mix is dry, the slump is zero

D. Concrete mix having zero slump, is unsuitable for high strength.

E. All the above.

 Answer Option E

15. You are asked to construct a massive dam, the type of cement you will use, is

A. ordinary Portland cement

B. rapid hardening cement

C. low heat cement

D. blast furnace slag cement

E. white cement.

 Answer Option C

16. The produce impermeable concrete

A. thorough mixing of concrete is required

B. proper compaction of concrete is required

C. proper curing of concrete is required

D. properly graded and non-porous aggregates are requied

E. all the above.

 Answer Option E

17. Water required per bag of cement, is

A. 7 kg

B. 14 kg

C. 21 kg

D. 28 kg

E. 35 kg

 Answer Option E

18. Pick up the incorrect statement from the following:

A. The bottom and top ends of slump mould are parallel to each other

B. The axis of the mould is perpendicular to the end faces

C. The internal surface of the mould is kept clean and free from set cement

D. The mould is in the form of a frustum of hexagonal pyramid

E. None of these.

 Answer Option D

19. ISI has specified full strength of concrete after

A. 7 days

B. 14 days

C. 21 days

D. 28 days

E. none of these.

 Answer Option E

20. For construction of structures in sea water, the cement generally preferred to, is

A. Portland-pozzolana cement

B. quick setting cement

C. low heat Portland cement

D. rapid hardening cement

E. none of these.

 Answer Option A

21. Percentage of pozzolanic material containing clay upto 80% used for the manufacture of pozzolana cement, is

A. 30%

B. 40%

C. 50%

D. 60%

E. 70%

 Answer Option A

22. For batching 1:3:6 concrete mix by volume, the ingredients required per bag of 50 kg cement, are:

A. 70 litres of sand and 120 litres of aggregates

B. 70 kg of sand and 140 litres of aggregates

C. 105 litres of sand and 140 litres of aggregates

D. 105 litres of sand and 210 litres of aggregates

E. none of these.

 Answer Option D

23. The process of hardening the concrete by keeping its surface moist is known

A. placing

B. wetting

C. curing

D. compacting

E. none of these.

 Answer Option C

24. The grade of concrete not recommended by I.S. : 456, is

A. M 100

B. M 200

C. M 300

D. M 400

E. M 500

 Answer Option E

25. C.R.R.I. charts are used to obtain a relatioship between strength of concrete and

A. water cement ratio

B. workability

C. grading of aggregate

D. fineness modulus

E. none of these.

 Answer Option A

26. Proper batching ensures

A. economy

B. durability

C. workability

D. strength

E. all the above.

 Answer Option E

27. Workability of concrete for a given water content is good if the aggregates, are

A. rounded aggregate

B. irregular aggregate

C. angular aggregate

D. flaky aggregates.

 Answer Option A

28. Pick up the correct statement from the following:

A. Bulking of sand is caused due to formation of a thin film of surface moisture

B. Fine sand bulks more than coarse sand

C. With 10% moisture content by weight, the bulking of sand is increased by 50%.

D. The volume of fully saturated sand, is equal to the volume of dry and loose sand

E. All the above.

 Answer Option E

29. For compacting plain concrete road surface of thickness less than 20 cm, we use

A. internal vibrator

B. screed vibrator

C. form vibrator

D. none of these.

 Answer Option B

30. Pick up the correct statement from the following:

A. Construction joints are necessarily planned for their locations

B. Expansion joints are provided to accommodate thermal expansion

C. Construction joints are provided to control shrinkage cracks

D. Expansion joints need not be provided in foundation concrete

E. All the above.

 Answer Option E

31. Pick up the correct statement from the following:

A. Segregation is necessary for a workable concrete

B. Consistency does not affect the workability of concrete

C. If the slump increases, workability decreases

D. If the concrete mix is dry, the slump is maximum

E. None of these.

 Answer Option E

32. Specified compressive strengh of concrete is obtained from cube tests at the end of

A. 3 days

B. 7 days

C. 14 days

D. 21 days

E. 28 days.

 Answer Option E

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

A. 2/3 mean dimension

B. 3/4 mean dimension

C. 3/5 mean dimension

D. 5/8 mean dimension

E. none of these.

 Answer Option C

34. Pick up the incorrect statement from the following:

A. A rich mix of concrete possesses higher strength than that a lean mix of desired workability with excessive equantity of water

B. The strength of concrete decreases as the water cement ratio increases

C. If the water cement ratio is less than 0.45, the concrete is not workable and causes honey-combed structure

D. Good compaction by mechanical vibrtions, increases the strength of concrete

E. None of these.

 Answer Option A

35. The percentage of the aggregate of F.M. 2.6 to be combined with coarse aggregate of F.M. 6.8 for obtaining the aggregates of F.M. 5.4, is

A. 30%

B. 40%

C. 50%

D. 60%.

 Answer Option C

36. The final operation of finishing floors, is known as

A. screeding

B. floating

C. trowelling

D. finishing

E. all the above.

 Answer Option C

37. The internal dimensions of a ware house are 15 m x 5.6 m, and the maximum height of piles is 2.70 m, the maximum number of bags to be stored in two piles, are

A. 1500 bags

B. 2000 bags

C. 2500 bags

D. 3000 bags

E. 4000 bags

 Answer Option D

38. For an ordinary Portland cement

A. residual does not exceed 10% when sieved through IS Sieve No. 9

B. soundness varies from 5 to 10 mm

C. initial setting time is not less than 30 minutes

D. compressive stress after 7 days, is not less than 175 kg/cm2

E. all the above.

 Answer Option C

39. The maximum thickness of concrete floor of a cement warehouse, is

A. 10 cm

B. 15 cm

C. 20 cm

D. 25 cm

E. 30 cm

 Answer Option D

40. A construction joint is provided where

A. bending moment is small

B. shear force is small

C. the member is supported by other member

D. all the above.

 Answer Option D

41. The compaction of concrete, improves

A. density

B. strength

C. durability

D. all the above.

 Answer Option D

42. Pick up the correct statement from the following:

A. Water cement paste hardens due to hydration

B. During hardening cement binds the aggregates together

C. Cement provides strength, durability and water tightness to the concrete

D. All the above.

 Answer Option D

43. The light weight aggregates are obtained from

A. sedimentary rocks

B. metamorphic rocks

C. igneous rocks

D. volcanic source.

 Answer Option D

44. If the depth of moist sand in a cylinder is 15 cm and the depth of the sand when fully inundated with water is 12 cm, the bulking of the moist sand, is

A. 10%

B. 12%

C. 15%

D. 20%

E. 25%.

 Answer Option E

45. Pick up the correct statement from the following:

A. According to the petrological characteristics, concrete aggregates are classified as heavy weight, normal weight and light weight

B. According to the shape of the particles, concrete aggregates are classified as rounded irregular, angular and flaky

C. According to the surface texture of the particles, the concrete aggregates are classified as glassy, smooth, granular, rough, crystalline, honey combed and porous

D. All the above.

 Answer Option D

46. Segregation is responsible for

A. honey-combed concrete

B. porous layers in concrete

C. surface scaling in concrete

D. sand streaks in concrete

E. all the above.

 Answer Option E

47. Addition of pozzolana to cement

A. decreases workability

B. increases strength

C. increases heat of hydration

D. decreases curing time

E. none of these.

 Answer Option E

48. The datum temperature for maturity by Plowman, is

A. 23°C

B. 0°

C. - 5.6°C

D. - 11.7°C

 Answer Option D

49. Pick up the incorrect statement from the following:

A. The degree of grinding of cement, is called fineness

B. The process of changing cement paste into hard mass, is known as setting of cement

C. The phenomenon by virtue of which cement does not allow transmission of sound, is known as soundness of cement

D. The heat generated during chemical reaction of cement with water, is known as heat of hydration

E. None of these.

 Answer Option C