Concrete Technology problems
- 1. For compacting plain concrete road surface of thickness less than 20 cm, we use
Options- A. internal vibrator
- B. screed vibrator
- C. form vibrator
- D. none of these. Discuss
Correct Answer: screed vibrator
- 2. Specified compressive strengh of concrete is obtained from cube tests at the end of
Options- A. 3 days
- B. 7 days
- C. 14 days
- D. 21 days
- E. 28 days. Discuss
Correct Answer: 28 days.
- 3. Addition of pozzolana to cement
Options- A. decreases workability
- B. increases strength
- C. increases heat of hydration
- D. decreases curing time
- E. none of these. Discuss
Correct Answer: none of these.
- 4. For construction of structures in sea water, the cement generally preferred to, is
Options- A. Portland-pozzolana cement
- B. quick setting cement
- C. low heat Portland cement
- D. rapid hardening cement
- E. none of these. Discuss
Correct Answer: Portland-pozzolana cement
- 5. The grade of concrete not recommended by I.S. : 456, is
Options- A. M 100
- B. M 200
- C. M 300
- D. M 400
- E. M 500 Discuss
Correct Answer: M 500
- 6. Segregation is responsible for
Options- A. honey-combed concrete
- B. porous layers in concrete
- C. surface scaling in concrete
- D. sand streaks in concrete
- E. all the above. Discuss
Correct Answer: all the above.
- 7. The final operation of finishing floors, is known as
Options- A. screeding
- B. floating
- C. trowelling
- D. finishing
- E. all the above. Discuss
Correct Answer: trowelling
- 8. The produce impermeable concrete
Options- A. thorough mixing of concrete is required
- B. proper compaction of concrete is required
- C. proper curing of concrete is required
- D. properly graded and non-porous aggregates are requied
- E. all the above. Discuss
Correct Answer: all the above.
- 9. According to the recommendations of IS : 456-1978, the expansion joints
Options- A. are provided where plane changes abruptly
- B. are provided to ensure minimum resistance
- C. are supported on separate columns
- D. do not carry reinforcement across them
- E. all the above. Discuss
Correct Answer: all the above.
- 10. The datum temperature for maturity by Plowman, is
Options- A. 23°C
- B. 0°
- C. - 5.6°C
- D. - 11.7°C Discuss
Correct Answer: - 11.7°C
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