Concrete technology-questions

mcq

1. Questions to Practice Concrete Technology

2. 1. Poisson’s ratio for concrete A.  remains constant B.  increases with richer mixes C.  decreases with richer mixes D.  none of the above

3. 2. The bulk density of aggregate depends upon its A.  Shape B.  Grading C.  Compaction D.  All of the above

4. 3. The types of aggregates of same nominal size which contains less void when compared A.  Rounded Spherical B.   Iregular C.  Flaky D. None of the above

5. 4. Strain in concrete at zero stress A.  Creep B.  Relaxation C.  Shrinkage D.  Transfer stress

6. 5. Steam curing is used in A.  Columns only B.  Long slabs and column C.  Mass production of precast concrete D.  All of the above

7. 6. The concrete may attain its 100% compressive strength after A.  14 days B.  28 days C.  1 year D.  3 years

8. 7. The pH value of water used for mixing and curing shall generally be not less than A.  3 B.  4 C.  5 D.  6

9. 8. The resistance of aggregate to wear is A.  Shear Value B.  Crushing Value C.  Abrasion Value D.  Impact value

10. 9. The most commonly used admixture which prolongs the setting time and hardening time is A.  Calcium Chloride B.  Sodium Silicate C.  Gypsum D. All of the above

11. 10. After casting an ordinary cement concrete, on drying A.  Expands B.  Mix C.  Shrinks D. None of the above

12. 11. The minimum water cement ratio to obtain workable concrete is A.  0.65 B.  0.50 C.  0.55 D. 0.40

13. 12. The advantage of adding pozzolana to lime is A.  To reduce the shrinkage B.  To increase resistant to cracking C.  To impart the shrinkage D . All of the above

14. 13. With the increase in moisture content, the bulking of sand A.  Increases B.  Decreases C.  First increases to a certain maximum value and then decreases D . First decreases to a certain minimum value and increases

15. 14. With the increase in moisture content, the bulking of sand A.  Increases B.  Decreases C.  First increases to a certain maximum value and then decreases D . First decreases to a certain minimum value and increases

16. 15. Increase in moisture content in concrete A.  Does not change the strength B.  Reduces the strength C . Increase the strength D . All of the above

17. 16. Light weight concrete is prepared by A.  Mixing Portland cement with sawdust B.  Using coke breeze, cinder or slag C . Mixing aluminium D . None of the above

18. 17. Minimum particle size of coarse aggregate is A.  2.5mm B.  4.75mm C . 5.85mm D . 6.5mm

19. 18. Workability of concrete is expressed by A.  Water cement ratio B.  slump value C . Both A and B D . Compaction factor

20. 19. For high degree of workability the slump value should vary between A.  0-25mm B.  25-50mm C . 50-80mm D . 80-100mm

21. 20. The inert material of cement concrete mix A.  water B.  cement C . aggregate D . None of the above

22. 21. Curing A.  reduces the shrinkage of concrete B.  preserves the properties of concrete C . Preserves the loss of water by evaporation D . All of the above

23. 22. Expansion joints are provided if the length of the concrete structure exceeds A.  45m B.  35m C . 25m D . 15m

24. 23. Efflorescence in cement is caused due to excess of A.  Silica B.  Lime C . Alkalies D . Commitees

25. 24. Slump test of concrete is measure of its A.  Impact vale B.  Consistency C . Tensile strength D . Compressive strength

26. 25. An admixture A.  Is a basic ingredient of concrete B.  Offers improvement not economically attained by adjusting mix proportions C . Is a substitute for good concreting practice D . In excess quantity may be beneficial to the properties of concrete

27. 26. The admixture added at the time of preparing the concrete mix is to reduce the quantity of water and produce high strength concrete is known as A.  Retarding admixtures B.  Accelerating admixtures C . Air entraining admixtures D . Super plasticizers

28. 27. Water cement ratio may be defined as the ratio of A.  Volume of water to that of cement in a concrete mix B.  Weight water to that of cement in a concrete mix C . Volume of water to that of concrete in a concrete mix D . Weight of water to that of concrete in a concrete mix

29. 28. Workability of concrete is directly proportional to A.  Aggregate cement ratio B.  Time of transit C . Grading of aggregate D . All of the above

30. 29. A badly mixed cement concrete results in A.  Segregation B.  Bleeding C . Honeycombing D . None of the above

31. 30. Strength of concrete increases with A.  Increase in water cement ratio B.  Increase in fineness of cement C . Decrease in curing time D . None of the above

32. 31. Workability is inversely proportional to A.  Time of transit B.  Water cement ratio C . Air in the mix D . Size of aggregate

33. 32. Use of calcium chloride in the concrete is to A.  Increase shrinkage and setting time B.  Decrease shrinkage and setting time C . Decrease shrinkage and increase setting time D . None of the above

34. 33. Minimum grade of concrete is to be used in RC A.  M15 B.  M20 C . M10 D . M25

35. 34. Modulus of rupture of concrete is a measure of A. Flexural tensile strength B.  Direct tensile strength C . Compressive strength D . Split tensile strength

36. 35. Air entrainment in concrete increases A. Workability B.   strength C . Effects of temperature variations D . Unit weight

37. 36. A rich mix of concrete is a mix with high content of A. Cement B.   Sand C . Fine aggregate D . Coarse aggregate

38. 37. Finer grinding of cement A. Affects only the early development of strength B.   Affects only the ultimate strength C . Both of above D . Does not affect strength

39. 38. The quantity of coarse aggregate and fine aggregate is slightly reduced when the concrete mix is A. To wet B.   Too dry C . Excessively plastic D . Too fat

40. 39. In case of high strength concrete, high increase in temperature A. Increase in strength of concrete B.   Has no affect on strength of concrete C . Decrease the strength of concrete D . Helps to harden the concrete fast for underwater concreting

41. 40. The gradual and continuous yielding of concrete which becomes permanent deformation when applied a load for sometime A. Bleeding B.   Creep C . Cribbling D . Setting

42. 41. Water cement ratio is generally expressed in volume of water required per A. 10 kg of cement B.   20 kg of cement C . 40 kg of cement D . 50 kg of cement

43. 42. The concrete from which entrained air and excess water are removed after placing in position, is known as A. Vacuum Concrete B.   Light weight concrete C . Prestressed concrete D . Saw dust concrete

44. 43. If the avg Compressive strength is 4000 kg/cm2 and standard deviation is 500, the coefficient of variation is A. 10% B.   12.5% C . 17,5% D . 22.5%

45. 44. If the avg Compressive strength is 4000 kg/cm2 and standard deviation is 500, the coefficient of variation is A. 10% B.   12.5% C . 17,5% D . 22.5%

46. 46. The bulking of sand is maximum if moisture content is approximately A. 4% B.   7% C . 15% D . None of the above

47. 47. The quantity of extra cement added , when mixing done by hand, should be A. 18% B.   15% C . 10% D . 5%

48. 48. Normal setting time of rapid hardening cement is A. 5 minutes B.   15 minutes C . 30 minutes D . 1 hour

49. 49. The temperature most favourable for placing concrete is A. ± 2 ºC B.   18 ± 2 ºC C . 27 ± 2 ºC D . 35 ± 2 ºC

50. 50. The slump adopted for heavy sections with vibrated concrete should be A. 12-25 mm B.   25-50mm C . 50-75mm D . 75-100mm

51. 50. Vicats apparatus is used for A. Fineness test B.   Consistency test C . Setting time test D . Soundness test

52. 51. Concrete having a slump of 6.5cm is said to be A. Dry B.   Earth moist C . Semi Plastic D . Plastic

53. 52. Concrete is unsuitable for compaction by a vibrator if it is A. Dry B.   Earth moist C . Semi Plastic D . Plastic

54. 53. For same design load the wt. of concrete in pre stressed concrete as compared to ordinary concrete can be reduced by A. 10% B.   20% C . 30% D . 50%

55. 54. The process of mixing,transportation,placing , compacting concrete using OPC of shouldn’t take more than A. 30 minutes B.   60 minutes C . 90 minutes D . 10 hour

56. 55. The flexural strength of concrete is determined by A. Beam test B.   Cube test C . Slump test D . Shear test

57. 56. The use of superplasticizer permit reduction of water extent upto A. 10% B.   30% C . 20% D . 23%

58. 57. Strength of cement concrete primarily depends upon A. Quality of water B.   Quantity of aggregate C . Quantity of cement D . Water cement ratio

59. 58. The maximum particle size of coarse aggregate A. 45mm B.   55mm C . 65mm D . 75mm

60. 59. The concrete mix which causes difficulty in obtaining smooth finish is know to possess A. Segregation B.   Bleeding C . Hardness D . Internal friction

61. 60. Shrinkage of concrete depends on A. Humidity of atmosphere B.   Passage of time C . Stress D . Both A and B