251. Durability of construction material is
- resistance to crushing
- resistance to weathering
- shear strength
- compressive strength
252. _________ is the quantity of fine aggregate required per 50 kg of cement of M 150 – 1 : 2 : 4 grade of concrete.
- 0.053 m3
- 0.340 m3
- 0.070 m3
- 0.035 m3
253. Light weight concrete is also known as
- low concrete
- lean concrete
- transparent concrete
- cellular concrete
254. Progressive increase in the inelastic deformation of concrete under sustained stress component is known as
- Shrinkage of concrete
- Creep of concrete
- Deformation of concrete
- Yielding of concrete
255. For making reinforced cement concrete, the pH of water is restricted to a minimum of
256. Which of the following is not a fully non-destructive testing of concrete?
- Rebound hammer
- Ultrasonic pulse velocity
- Profometer for rebar
257. Abrams law formulated in 1919 states that the strength of concrete varies inversely with the water/cement ratio. Which of the following condition needs to be satisfied for this law to the applicable?
- Cement should of good quality
- Water should be clean
- Compaction should be carried out with needle vibrators
- Chemical admixtures must be used
- The concrete should be fully compacted
258. Fly ash addition to concrete helps in
- improving workability, accelerates early strength gain
- reducing set time of concrete and improves finishibility.
- reducing the water demand, reducing heat of hydration and deleys the setting time of concrete.
- improve pumpability and reduces curing time.
- increasing the bleeding by reducing the heat of hydration.
259. An accelerating admixtures added to concrete performs the following functions
- accelerated water losses from concrete
- accelerates the curing of concrete
- increases rate of hydration of cement
- accelerates the deterioration of concrete
- accelerates the setting time of concrete
260. According to IS 456 : 2000, the recommended slump (in mm) range for in-situ piling using concrete is