Ethio Construction Engineering

1. Why is super plasticizer added to concrete?

1. To reduce the quantity of mixing water.
2. To increase the consistency.
3. To reduce the quantity of cement.
4. To increase resistance to freezing an thawing.

Select the correct answer using the codes given below:
a) 1 and 2 b) 2 and 3
c) 1 and 4 d) 1, 4 and 3

2. As per IS Code of Practice, concrete should be cured at

a) 5oC b) 10oC c) 27oC d) 40oC

3. The maximum bulking of sand is likely to occur at a moisture content of

a) 5% b) 8% c) 11% d) 14%

4. Which of the following aggregates gives maximum strength in concrete?

a) Rounded aggregate b) Elongated aggregate
c) Flaky aggregate d) Cubical aggregate

5. Which of the following pairs is not matched correctly with regard to coarse aggregate > 10 mm?

a) Strength - 10 per cent fine
b) Toughness - Impact test
c) Hardness - Abrasion set
d) Specific Gravity - Pyconometer

6. A gauged mortar is obtained by adding which of the following ingredients to cement?

a) Sandstone b) Sand and surkhi
c) Sand and lime d) Surkhi alone

7. Marble is quarried by

a) blasting b) excavating c) heating d) wedging

8. Which of the following stone has maximum % water absorption by volume?

a) Shale b) Granite c) Slate d) Quartzite

9. The chemical used to protect stones in industrial towns is

a) Ba (OH)2 b) CaCl2 c) H2SO4 d) caustic alkalis

10. The temperature range in a cement kiln is

a) 500oC to 1000oC b) 1000oC to 1200oC
c) 1300oC to 1500oC d) 1600oC to 2000oC

11. Which of the following pairs is not matched correctly?

(Cement Test) (Apparatus)

a) Fineness - Nurse and blains b) Consistency - Vicat
c) Soundness - Le-Chatelier d) Specific Gravity - Lea and Nurse

12. Rapid hardening cement attains early strength due to

a) larger proportion of lime grounded finer than normal cement.
b) lesser proportion of lime grounded coarser than normal cement.
c) lesser proportion of lime grounded finer than normal cement.
d) larger proportion of lime grounded coarser than normal cement.

13. Soundness test of cement determines

a) quality of free lime b) ultimate strength
c) durability d) initial setting

14. A first class brick when immersed in cold water for 24 hours should not absorb more than __ % of water of its dry weight.

a) 15% b) 20% c) 22% d) 25%

15. The percentage of alumina in a good brick earth lies between

a) 5% to 10% b) 20% to 30%
c) 50% to 60% d) 70% to 80%

16. Crushing strength of a first class brick should not be less than

a) 35 kg / cm3 b) 70 kg / cm2
c) 105 kg / cm2 d) 140 kg / cm2

17. The temperature at which bricks are burnt varies from:

a) 500oC to 700oC b) 700oC to 1000oC
c) 1000oC to 1200oC d) 1200oC to 1500oC

18. For one cubic metre of brick masonry, the number of modular bricks needed is

a) 400 or less b) 400 to 450
c) 500 to 550 d) 600 to 650

19. Gypsum is used as an admixture in cement grouts for

a) Accelerating the setting time
b) Retarding the setting time
c) Increasing the plasticity
d) Reducing the grout shrinkage

Answers / Key:

1-a; 2-c; 3-a; 4-d; 5-d; 6-c; 7-d; 8-a; 9-a; 10-c; 11-d; 12-a; 13-a; 14-a; 15-b; 16-c; 17-c; 18-c; 19-b

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