SupeConcrete Works Final Exam

1. Air voids generally larger than one millimeter which are not usually produced by the intentional use of an air entraining agent.

2. Degree of workability is dependent on :

3. The most important factor of concrete proportioning that affect the strength of concrete.

4. This type of cement is especially suited to improve the workability with smaller water-cement ratio and to improve frost resistance of concrete.

5. Equipment used in the consolidation of fresh concrete.

6. Large Maximum Sizes of well-grade aggregates have less voids than smaller sizes. Hence, concrete with larger sized aggregates require. less mortar per unit volume of concrete. The maximum size of aggregate should be the largest economically available and consistent with the dimension of the structure. ACI 3.3.2 – Nominal maximum size of coarse aggregate in a concrete mix shall be not larger than:

7. By an approved procedure admixture is added to each batch of concrete either of by weight or volume. What is the accuracy of measurement of admixtures into the mixer.

8. Which is true on conducting of a slump test?

9. A type of cement recommended for use in marine structures, sewage works, sewage works and for laying concrete under water such as bridges, piers, dams and mass concrete works.

10. The approximate volume of cement in a concrete mix?

11. Factors affecting the amount of water in the mixture:

12. The minimum flexural strength requirement of beam sample when tested by the third point of loading method.

13. Factors affecting the amount of water in the mixture:

14. The measurement of materials for making concrete

15. The quality of concrete is largely dependent upon ________________.

16. This cement has increased power against sulphates and is less reactive and initial setting time is greater than Ordinary Portland Cement.

17. Slump test on concrete is to measure _______________.

18. ACI 318-08: 5.8.3 For a job-mixed concrete, mixing shall be continued for at least ____________ seconds after all materials are in the drum, unless a shorter time is shown to be satisfactory by the mixing uniformity tests of “Specification for Ready-Mixed Concrete” (PNS/ASTM C 94).

19. The process of maintaining sufficient moisture and favorable temperature in concrete.

20. The strength of concrete is principally dependent on.

21. A hydraulic cement produced by pulverizing clinker consisting essentially of hydraulic calcium silicates, and usually containing calcium sulfate. It is most widely used type of cement which is suitable for all general concrete construction.

22. Because the paste surrounds and separates the individual aggregate particles in concrete, which one does not contribute largely to the strength of the concrete?

23. Air bubbles generally smaller than one millimeter incorporated in cement mortar during mixing, usually produced by the intentional use of an air-entraining agent.

24. Batching tolerance for Aggregates.

25. Which of the following is true on conducting a slump test?

26. When consolidating concrete during pouring operations, vibrator should not be operated in any one location longer than ___________.

27. Attains high strength in early days. It is used in concrete where formworks are removed at an early stage. It is used in prefabricated concrete and road works construction.

28. The ease in placing concrete without segregation into the final position where it is allowed to harden.

29. The additive used in mixing concrete.

30. For batch mixing at the site of construction or at a central point, the flow of water shall be uniform and all water should be in the drum by the end of the first ____________ seconds of the mixing period.

31. Which of the following is not a chemical admixture for concrete?

32. To attain a uniform consistency of concrete during the pouring operation of a concrete pavement if vibrated, the slump should not be more than:

33. Generally speaking, batching of concrete by volume is preferable than weight.

34. Concrete (other than high-early strength) shall be maintained above 10°C and in a moist condition for at least the first how many days after placement

35. When batches are hauled to the mixer, bulk cement shall be transported either in waterproof compartments or between the fine and coarse aggregate. When cement is placed in contact with moist aggregates, batches will be rejected unless mixed within __________ of such contact.

36. What is that state where the paste loses its fluidity and within a few hours a noticeable hardening occurs.

37. The minimum flexural strength requirement of beam sample when tested by midpoint method.

38. Type of concrete recommended for use where works is to be completed in very short period and for concreting in static or running water.

39. A test to determines the consistency of concrete.

40. The additive used in mixing concrete.

41. For small project where quantity of steel bars is 10,000kg or less, what is the basis of acceptance of material?

42. Although bar supports are not concrete reinforcing agents, its use is necessary in __________________________________.

43. Regarding flame-cutting (oxy-acetylene) of reinforcement bars, tests have shown that any effect of flame-cutting is localized to the end-cut surfaces. Only a very short distance, approximately ______ mm from the flame-cut ends is affected.

44. The standard hook for stirrup and tie, No 8 bar and smaller is 135-degree bend plus ______ extension at free end of bar, where db = bar diameter.

45. In concrete, proper coverage of the bars is required to prevent what condition(s) from developing?

46. In spirally reinforced compression members, lap splice length of bars within a spiral shall be permitted to be multiplied by ______, but lap length shall not be less than 12 inches.

47. According to CRSI Manual of Standard Practice (Concrete Reinforcing Steel Institute), which of the following is not an approved type of reinforcement support

48. There is 1-QT RSB required for every .

49. Incorrect reinforcing steel placement can and has led to serious concrete structural failures. For example, lowering the top bars or raising the bottom bars by ½ inch more than that specified in a 6-inch-deep slab could reduce its load-carrying capacity by _________.

50. The standard hook for stirrup and tie, No. 6, No. 7, No. 8, is 90-degree bend plus ______ extension at free end of bar, where db = bar diameter

51. In general, the minimum concrete cover for primary reinforcement of concrete not exposed to weather or in contact with the ground should be:

52. When bars of different size are lap spliced in compression, splice length shall be the larger of ldc of larger bar and compression lap splice length of smaller bar. Lap splices of ______________ and smaller bars shall be permitted.

53. In walls and slabs other than concrete joist construction, primary flexural reinforcement shall not be spaced farther apart than three times the wall or slab thickness, nor farther apart than ____________.

54. A tie bar should be .

55. PNS 49:1986, has the dash or number marked on reinforcing bars signifying the grade (tensile strength), which grade of reinforcement that has no dash in it?

56. Trial fabrication subject for approval by an authorized representative prior to mass production.

57. In footings between the ground and steel, what minimum thickness of concrete cover, in inches, should be provided?

58. A full mechanical splice shall develop in tension or compression, as required, at least __________ of the bar.

59. Lap splices shall not be used for bars larger than __________.

60. A dowel bar should be .

61. PNS has the Color Code painted on the surface of the ends of each bar signifying its grade (tensile strength). White-Grade 230, Yellow-Grade275, Green-Grade 415, weldable bars is signified by what color?

62. Put in sequence the processes involve in fabrication of reinforcement bars.

63. The standard hook for stirrup and tie, No 5 bar and smaller is 90-degree bend plus ______ extension at free end of bar, where db = bar diameter

64. When splicing 1/2-inch-thick rebar of reinforcing steel without the benefit of drawing specifications, what is the minimum distance, in inches, that you should lap the bar?

65. The minimum clear spacing between parallel bars in a layer shall be db, but not less than ___________. (db = nominal diameter of the bar).

66. What tie is most often used in floor slabs?

67. The grade designation of a reinforcing steel bar.

68. Which one should not consist in bundling reinforcing bars of bigger quantities.

69. The sample of reinforcing steel bars for every 10,000 kgs shall be

70. Bundles and lifts should be securely tied with a minimum No. ____ gage wire for large bundles and/or lifts.