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
- There is no recognized limits have been laid down for crushing value
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.
163. Which of the following is not a type of void in concrete?
- Water void
- Air void
- Gel void
- Soil void
164. Compaction factor apparatus is used to measure which of the following properties of concrete?
- Compatibility with admixture
165. The minimum period before stripping the framework for props to slabs spanning 6 m is
- 16-24 h
- 3 days
- 7 days
- 21 days
- 14 days
166. Ultrasonic pulse velocity measurements may be used to establish
- homogeneity of concrete
- presence of cracks and voids
- quality of concrete in relation to standard requirements
- all the above
167. The corrosion of steel in reinforced concrete structures can be assessed by non-destructive testing using the principle
- Linear polarization resistance technique
- Ultrasonic Pulse Velocity Method
- Acoustic emission technique
- Computer Tomography
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
- M 25
- M 35
- M 30
- M 40
169. Modular ratio ‘m’ for M 25 grade of concrete is
170. Minimum cement content required for M 35 grade of concrete for very severe exposure condition as per IS 456 – 2000 is ___________ kg/m3.