Civil Engineering - Concrete Technology MCQs Part 5

1. Concrete is unsuitable for compaction by a vibrator if it is

A.
dry

B.
earth moist

C.
semi-plastic

D.
plastic

E.
none of these.

 Answer Option D

2. Inert material of a cement concrete mix, is

A.
water

B.
cement

C.
aggregate

D.
none of these.

 Answer Option C

3. Sands of zone I are

A.
coarse

B.
medium

C.
medium to fine

D.
fine.

 Answer Option A

4. The lower water cement ratio in concrete, introduces

A.
smaller creep and shrinkage

B.
greater density and smaller permeability

C.
improved frost resistance

D.
greater wear resistance and improved bond strength

E.
all the above.

 Answer Option E

5. The cement becomes useless if its absorbed moisture content exceeds

A.
1%

B.
2%

C.
3%

D.
4%

E.
5%

 Answer Option E

6. A concrete using an air entrained cement

A. has strength less than 10% to 15%

B. has more resistance to weathering

C. is more plastic and workable

D. is free from segregation and bleeding

E. all the above.

 Answer Option C

7. Pick up the correct statement from the following:

A. The maximum size of a coarse aggregate, is 75 mm and minimum 4.75 mm

B. The maximum size of the fine aggregate, is 4.75 mm and minimum 0.075 mm

C. The material having particles of size varying from 0.06 mm to 0.002 mm, is known as silt

D. The material having particles of size less than 0.002 mm, is known as clay

E. All the above.

 Answer Option E

8. Placing of concrete should preferably be done at a temperature of

A. 0°C

B. 10°C

C. 20°C

D. 23°C

E. 27 ± 2°C

 Answer Option E

9. The aggregate impact value of the aggregate used in

A. building concrete is less than 45

B. road pavement concrete is less than 30

C. runway concrete is less than 30

D. all the above.

 Answer Option D

10. The maximum percentage of chemical ingredient of cement is that of

A. magnesium oxide

B. iron oxide

C. aluminium

D. lime

E. silica.

 Answer Option D

11. Pick up the incorrect statement from the following:

A. Workability of the concrete mix decreases with an increase in the moisture content

B. Concrete for which preliminary tests are conducted, is called controlled concrete

C. Bulking of sand depends upon the fineness of grains

D. Concrete mix 1 : 6 : 12, is used for mass concrete in piers.

E. All the above.

 Answer Option E

12. Sand generally contains salt if it is obtained from:

A. nala beds

B. river beds

C. sea beds

D. all the above

E. none of these.

 Answer Option C

13. The impurity of mixing water which affects the setting time and strength of concrete, is

A. sodium sulphates

B. sodium chlorides

C. sodium carbonates and bicarbonates

D. calcium chorides

E. calcium bicarbonates

 Answer Option C

14. Pick up the correct statement from the following:

A. Continuous grading is not necessary for obtaining a minimum of air voids

B. The omission of a certain size of aggregate is shown by a straight horizontal line on the grading curve

C. The omission of a certain size of aggregate in concrete increases the workability but also increases the liability to segregation

D. All the above.

 Answer Option D

15. Di-calcium silicate (C2S)

A. hydrates rapidly

B. generates less heat of hydration

C. hardens rapidly

D. provides less ultimate strength to cement

E. has less resistance to sulphate attack.

 Answer Option B

16. On a grading curve, the gap grading is represented by

A. a horizontal line

B. a vertical line

C. N.W. inclined line

D. N.E. inclined line

E. none of these.

 Answer Option A

17. Bulking of sand is

A. mixing of different sizes of sand particles

B. mixing of lime with sand

C. maximum water with sand

D. swelling of sand when wetted.

 Answer Option D

18. Curing of pavements, floors, roofs and slabs, is done by

A. membrane method

B. ponding method

C. covering surface with bags

D. sprinkling water method

E. shading concrete method.

 Answer Option B

19. Pick up the incorrect statement from the following:

A. With passage of time, the strength of cement increases

B. With passage of time, the strength of cement decreases

C. After a period of 24 months, the strength of cement reduces to 50%

D. The concrete made with storage deteriorated cement, gains strength with time

E. None of these.

 Answer Option A

20. The surface where two successive placements of concrete meet, is known as

A. Contraction joint

B. Expansion joint

C. Construction joint

D. both (a) and (b)

E. both (6) and (c).

 Answer Option C

21. An excess of flaky particles in concrete aggregates

A. decreases the workability

B. increases the quantity of water and sand

C. affects the durability of concrete

D. more than 15% are not desirable

E. all the above.

 Answer Option E

22. 1.S.I. has specified the full strength of concrete after

A. 7 days

B. 14 days

C. 21 days

D. 28 days

E. 35 days

 Answer Option D

23. For given workability the grading requiring the least amount of water is one that gives

A. greatest surface area for the given cement and aggregates

B. least surface area for the given cement and aggregates

C. least weight for the given cement and aggregates

D. greatest weight for the given cement and aggregates

E. none of these.

 Answer Option A

24. The minimum percentage of chemical ingredient of cement is that of

A. magnesium oxide

B. iron oxide

C. alumina

D. lime

E. silica.

 Answer Option A

25. The specifications of a cement bag for storage, are

A. weight 50 kg

B. height 18 cm

C. plan area 3000 sq. cm

D. volume 35 litres

E. all the above.

 Answer Option E

26. The bulk density of aggregates, depends upon

A. shape

B. grading

C. compaction

D. all the above.

 Answer Option D

27. Pick up the correct statement from the following:

A. The bulk density of fine aggregate is usually about 10 per cent more than that of coarse aggregate of similar composition

B. The specific gravity of aggregate is important for the determination of the moisture content

C. The absorption and porosity of an aggregate influence the property of the concrete

D. A highly absorptive aggregate reduces the workability of concrete considerably

E. All the above.

 Answer Option E

28. Horizontal construction joints in concrete walls are generally provided at

A. soffit level

B. window sill level

C. floor level

D. all the above.

 Answer Option D

29. Pick up the correct statement from the following:

A. Construction joints in columns are provided a few cm below the junction of beam

B. Construction joints in columns are provided at the bottom haunching

C. Construction joints in beams and slabs are provided within middel third

D. Constructionjoints are generally provided in positions subjected to least shear force

E. All the above.

 Answer Option E

30. For a concrete mix 1:3:6 and water cement ratio 0.6 both by weight, the quantity of water required per bag, is

A. 10 kg

B. 12 kg

C. 14 kg

D. 16 kg

E. 20 kg

 Answer Option C

31. The concrete mix which causes difficulty in obtaining a smooth finish, possess

A. segregation

B. internal friction

C. harshness

D. bleeding

E. none of these.

 Answer Option C

32. Le-Chatelier's apparatus is used for testing

A. soundness of cement

B. hardness of cement

C. strength of cement

D. durability of cement.

 Answer Option A

33. 'Ware house pack' of cement means

A. full capacity of the ware house

B. pressure exertion of the bags of upper layers

C. pressure compaction of the bags on lower layers

D. packing the ware house

E. none of these.

 Answer Option C

34. In the method of voids for determination of the quantity of cement paste, it is assumed that

A. Voids in coarse aggregates are filled by fine aggregates

B. Voids in fine aggregates are filled by the cement paste

C. Volume of fine aggregates is equal to total voids in coarse aggregates plus 10% extra

D. Volume of cement paste required is equal to total volume of voids in fine aggregates plus 15% extra

E. All the above.

 Answer Option E

35. If a grading curve is horizontal bet-wen the portions of 20 mm I.S. Sieve and 4.75 mm I.S. Sieve, the graded aggregates do not contain

A. 20 mm particles

B. 10 mm particles

C. 4.75 mm particles

D. all the above.

 Answer Option D

36. The size of fine aggregates does not exceed

A. 2.75 mm

B. 3.00 mm

C. 3.75 mm

D. 4.75 mm

E. 5.75 mm

 Answer Option D

37. An aggregate is known as cyclopean aggregate if its size is more than

A. 4.75 mm

B. 30 mm

C. 60 mm

D. 75 mm

E. 90 mm.

 Answer Option D

38. The main object of compaction of concrete, is:

A. to eliminate air holes

B. to achieve maximum density

C. to provide initimate contact between the concrete and embedded materials

D. all the above.

 Answer Option D

39. Pick up the correct statement from the following:

A. The quality of water governs the strength of concrete

B. The quantity of water required for concreting, depends upon the grading of aggregate amd method of compaction

C. 10% excess of water reduces the strength of concrete by 15%

D. 30% excess of water reduces the strength of concrete by 50%

E. All the above.

 Answer Option E

40. Particles of 0.002 mm size are that of

A. clay

B. sand

C. gravel

D. none of these.

 Answer Option A

6. A concrete using an air entrained cement

A. has strength less than 10% to 15%

B. has more resistance to weathering

C. is more plastic and workable

D. is free from segregation and bleeding

E. all the above.

 Answer Option C

7. Pick up the correct statement from the following:

A. The maximum size of a coarse aggregate, is 75 mm and minimum 4.75 mm

B. The maximum size of the fine aggregate, is 4.75 mm and minimum 0.075 mm

C. The material having particles of size varying from 0.06 mm to 0.002 mm, is known as silt

D. The material having particles of size less than 0.002 mm, is known as clay

E. All the above.

 Answer Option E

8. Placing of concrete should preferably be done at a temperature of

A. 0°C

B. 10°C

C. 20°C

D. 23°C

E. 27 ± 2°C

 Answer Option E

9. The aggregate impact value of the aggregate used in

A. building concrete is less than 45

B. road pavement concrete is less than 30

C. runway concrete is less than 30

D. all the above.

 Answer Option D

10. The maximum percentage of chemical ingredient of cement is that of

A. magnesium oxide

B. iron oxide

C. aluminium

D. lime

E. silica.

 Answer Option D