221. As compared to moist cured concrete the permeability of steam cured concrete is
- more
- less
- same
- none of the above
222. If fineness modulus of aggregate is 4.1 then it is
- Fine sand
- Coarse sand
- All in aggregate
- Coarse aggregate
223. For aggregate ratio of order of _______, the workability is independent of the Aggregate Cement Ratio.
- 1.0
- 1.5
- 2.0
- 3.0
224. Polymer concrete is most suitable for
- sewage disposal works
- mass concreting works
- insulating exterior walls of an air-conditioned building
- road repair works
225. The cement and water slurry coming on the top and setting on the surface is called
- Crazing
- Efflorescence
- Sulphate deterioration
- Laitance
226. A sample of concrete is prepared by using 500 g of cement with water cement ratio of 0.55 and 240 N/mm2 intrinsic strength of gel. The theoretical strength of concrete on full hydration will be nearly.
- 148 N/mm2
- 126 N/mm2
- 104 N/mm2
- 82 N/mm2
227. The strength of a fully matured concrete sample is 500 kg/cm2. When cured at an average temperature of 20°C in day, 10°C in night, datum temperature T0, is -11°C. If Plowman constants A is 32 and B is 54, the strength of identical concrete at 7 days will be nearly
- 333 kg/cm2
- 312 kg/cm2
- 272 kg/cm2
- 243 kg/cm2
228. Consider the following data for concrete with mild exposure:
Water / cement ratio = 0.50
Water = 191.6 litre
The required cement content will be
- 561 km/m3
- 472 km/m3
- 383 kg/m3
- 294 kg/m3
229. Which one of the following light weight element will be added to enhance the protective properties for X-ray shielding mortars?
- Sodium
- Potassium
- Lithium
- Calcium
230. For a given environment, the most significant factor that influences the total shrinkage of concrete is
- cement content of mix
- total amount of water added at the time of mixing
- size of the member concreted
- maximum size of the coarse aggregate used