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/mm^{2} intrinsic strength of gel. The theoretical strength of concrete on full hydration will be nearly.

- 148 N/mm
^{2} - 126 N/mm
^{2} - 104 N/mm
^{2} - 82 N/mm
^{2}

227. The strength of a fully matured concrete sample is 500 kg/cm^{2}. 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/cm
^{2} - 312 kg/cm
^{2} - 272 kg/cm
^{2} - 243 kg/cm
^{2}

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/m
^{3} - 472 km/m
^{3} - 383 kg/m
^{3} - 294 kg/m
^{3}

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