This set of Concrete Technology Multiple Choice Questions & Answers (MCQs) focuses on “Concrete Repair System”.
1. Air entrainment in concrete increases ____________
a) Strength
b) Workability
c) The effect of temp variations
d) The unit weight
View Answer
Explanation: There are following types of Air entrainment in concrete which helps to increase the workability.
2. In a dry environment, concrete strength will be loosed as much as ___________ % in moist environment.
a) 30
b) 40
c) 50
d) 60
View Answer
Explanation: Laboratory tests show that concrete strength will be loosed as much as 50% in dry environment as compared to moist environment.
3. Concrete placed in cold weather will take ____________ time to gain strength.
a) No
b) Less
c) More
d) Equal to hot weather
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Explanation: Concrete placed in cold weather will take longer time to gain strength, delaying form removal and subsequent construction.
4. After finishing concrete surface must be kept ___________
a) Dry
b) First dry it and then wet it
c) First wet it and then dry it
d) Wet
View Answer
Explanation: After finishing concrete surface must be kept wet, so that it’d be prevented from evaporation.
5. Dry intervals in surface wetting leads to ___________
a) Cracking
b) Fogging
c) High strength
d) Good workability
View Answer
Explanation: Dry intervals or patches can lead to crazing or cracking on the slab surface.
6. Damp proofing ____________ resist water well enough.
a) Does
b) Does not
c) Doesn’t effect
d) Depends on the temperature
View Answer
Explanation: Damp proofing does not resist water well enough to prevent oversaturation from ground water, or excessive and constant humidity.
7. Chemically active pore fillers ____________ the setting of concrete.
a) Retards
b) Decrease
c) Accelerates
d) No change
View Answer
Explanation: Chemically active pore fillers accelerates the setting of concrete and thus render the concrete more impervious at an early age.
8. Chemically inactive pore fillers ____________ the workability.
a) Decrease
b) Increase
c) Don’t affect
d) Improve
View Answer
Explanation: Chemically inactive pore fillers improve the workability and to facilitate the reduction of water for given workability and to make dense concrete which is basically impervious.
Sanfoundry Global Education & Learning Series – Concrete Technology.
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