This set of Basic Civil Engineering Multiple Choice Questions & Answers (MCQs) focuses on “Tests on Bricks”.
1. In absorption test on brick, how many hours it has to be soaked in cold water?
a) 19 hours
b) 5 hours
c) 6 hours
d) 24 hours
Explanation: The sample brick is oven dried, cooled and then soaked in water at room temperature for 24 hours.
2. What is the loading rate used in compressive strength test?
a) 14 N/mm2 per hour
b) 14 N/mm2 per minute
c) 20 N/mm2 per minute
d) 40 N/mm2 per hour
Explanation: As per IS codes, the loading on brick specimen in a CTM should be uniform at rate of 14 N/mm2 per minute.
3. How is the hardness of brick tested?
a) Using finger nail
b) Using hardness apparatus
c) Using hammer
d) Using chisel
Explanation: Brick is scratched using finger nail. If there are no visible scratches made on the brick surface, it is said to be sufficiently hard.
4. What is the maximum permissible tolerance for length and width respectively?
a) ± 3mm and ± 6mm
b) ± 6mm and ± 3mm
c) ± 3cm and ± 6cm
d) ± 6cm and ± 3cm
Explanation: The standard size of brick is length – 190mm and width – 90mm. When manufactured, size variations may occur by expansion or contraction while drying and burning process. Permissible tolerance is ± 6mm for length and ± 3mm for width and height.
5. What should be observed ideally when two bricks are struck together?
a) Dull sound
b) Sides shatter
c) Clear ringing sound
d) Brick breaks
Explanation: It is a test for soundness of brick. A sound brick should not break. It should produce a clear ringing sound. A dull sound indicates an unsound brick.
6. End of a brick is placed in a glass dish containing water and it is tested for efflorescence after it is absorbed or evaporated.
Explanation: After first evaporation, sample is dried. Then again same procedure is repeated. It is after second evaporation, brick is tested for efflorescence.
7. When observed efflorescence is more than 10% but less than 50% of the exposed area, it is:
a) Moderate efflorescence
b) Serious efflorescence
c) Heavy efflorescence
d) Light efflorescence
Explanation: For slight efflorescence, it should not cover more than 10% of the exposed surface and for heavy efflorescence, area should be more than 50%.
8. How is the structure of brick tested?
a) Powdered and tested
b) Immersed in water and dried.
c) Rubbed against another brick
d) Broken and examined
Explanation: A brick is broken to expose the surface. It should be uniform, compact, free from voids.
9. Creep test is carried out in accordance with:
a) IS 1528
b) IS 5688
c) IS 3495
d) IS 4568
Explanation: Creep test is done to check percent of shrinkage of refractory test piece under constant load. The specifications for this test are given in IS 1528.
10. What does M1 indicate in the formula:
% water absorption = M2 – M1 ⁄M2 x 100
a) Oven dried mass of brick
b) Oven dried and cooled mass of brick
c) Mass of water absorbed brick
d) Mass of water absorbed and dried brick
Explanation: Oven dried samples is allowed to cool down and its mass is taken as M1. Sample is immersed in water for 24 hours, excess water is wiped off and then its mass is taken as M2.
Sanfoundry Global Education & Learning Series – Basic Civil Engineering.
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