Concrete Technology MCQ – Aggregate MCQ

51. Aerated concrete is produced by addition of

1. copper sulphate
2. aluminium powder
3. sodium silicate
4. zinc insulation

52. One of the main demerits in using the lime mortar is that it

1. does not set quickly
2. is not durable
3. is plastic
4. swells

53. Which of the following impurities in the mixing water is having the highest destructive effect for concrete?

1. Calcium chloride
2. Lead nitrate
3. Alkalies
4. Algae

54. The cyclopean aggregate has a size more than

1. 4.75 mm
2. 25 mm
3. 45 mm
4. 75 mm

55. For a concrete mix ratio of 1 : 2 : 4, the bulking of sand is 15%. If bulking correction is not applied to sand, then what would be the ratio of dry sand per unit volume of cement?

1. 2
2. 2.35
3. 1.74
4. data insufficient

56. The ratio of 28 days minimum compressive strength of mortar grade M1 to M2 is

1. 3.0
2. 0.67
3. 1.5
4. 0.33

57. The length of time for which a concrete mixture will remain plastic is usually more dependent on

1. the setting time of cement than on the amount of mixing water the atmospheric temperature
2. the atmospheric temperature than on the amount of mixing water and setting time of cement
3. the setting time of cement than on the amount of mixing water than on atmospheric temperature
4. the setting time of mixing water used and the atmospheric temperature than on the setting time of cement

58. Aggregate impact value indicates ________ of Aggregates.

1. durability
2. toughness
3. hardness
4. strength

59. Strength of concrete is maximum in

1. twisting
2. fatigue
3. compression
4. shear

60. Separation of water or water sand cement from a freshly concrete is knows

1. flooding
2. segregation
3. creeping
4. bleeding