Concrete Technology MCQ – Aggregate MCQ

161. AS per IS 383, code of specifications, the desirable limit for crushing value of coarse aggregates used for concrete other than wearing surface is

  1. 10%
  2. 45%
  3. There is no recognized limits have been laid down for crushing value
  4. 25%
Answer
Answer. b

162. It is known that a concrete mix has 180 kg/m3 of water, 315 kg/m3 of sand. What is the coarse aggregate content in kg/m3, if the air content in the concrete is ignored?

Assume the specific gravities of cement, fines, sand and coarse aggregate to be 3.15, 2.98, 2.64 and 2.74 respectively.

  1. 1288
  2. 1488
  3. 1188
  4. 1388
Answer
Answer. a

163. Which of the following is not a type of void in concrete?

  1. Water void
  2. Air void
  3. Gel void
  4. Soil void
Answer
Answer. d

164. Compaction factor apparatus is used to measure which of the following properties of concrete?

  1. Consistency
  2. Compatibility
  3. Compatibility with admixture
  4. Cohesiveness
Answer
Answer. a

165. The minimum period before stripping the framework for props to slabs spanning 6 m is

  1. 16-24 h
  2. 3 days
  3. 7 days
  4. 21 days
  5. 14 days
Answer
Answer. e

166. Ultrasonic pulse velocity measurements may be used to establish

  1. homogeneity of concrete
  2. presence of cracks and voids
  3. quality of concrete in relation to standard requirements
  4. all the above
Answer
Answer. d

167. The corrosion of steel in reinforced concrete structures can be assessed by non-destructive testing using the principle

  1. Linear polarization resistance technique
  2. Ultrasonic Pulse Velocity Method
  3. Acoustic emission technique
  4. Computer Tomography
Answer
Answer. a

168. On inspection of the damaged reinforced concrete (RCC) elements of a pier on the sea coast (with surface of members in tidal zone), it is seen that M 20 concrete was used for the RCC works. As per IS 456 : 2000, the minimum grade of concrete to be used for the works would be

  1. M 25
  2. M 35
  3. M 30
  4. M 40
Answer
Answer. d

169. Modular ratio ‘m’ for M 25 grade of concrete is

  1. 18.67
  2. 13.33
  3. 10.98
  4. None
Answer
Answer. c

170. Minimum cement content required for M 35 grade of concrete for very severe exposure condition as per IS 456 – 2000 is ___________ kg/m3.

  1. 360
  2. 340
  3. 320
  4. 300
Answer
Answer. b
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