conc. tech online assignment

Method that is convenient for pouring large amount of high flowable concrete in under water concreting

• Tremie method

• Pumping method

• Hydro valve method

• Pneumatic valve method

In placing concrete under water using Tremie method -------method is followed for less flowable concrete

• Bulged

• Layered

• none of the above

• All of the above

In hydro valve method , ---------- & ---------are the resistive forces that is suddenly overcame by concrete weight

• Gravity & hydrostatic forces

• friction and gravity

• Friction inside pipe and hydrostatic forces

• Weight of concrete & friction

The ----------method of underwater concreting is suitable for cases where a large mass of concrete is required for stabilizing foundations and small amount of concrete is needed for different locations.

• Bagged concrete

• preplaced aggregate

• toggle bag

• skip method

Concrete placed at an atmospheric temperature------- degree centigrade is considered as hot weather concreting

• above 5

• above 20

• above 30

• above 40

--------- is not an effect of hot weather concreting

• hydration of cement

• delay in setting & hardening

• quick setting

• early stiffening.

------ is not a step to control defects in mass concrete

• Lowering water-cement ratio

• appropriate detailing of reinforcement

• Use of blended cement

• Use of fly ash in high volume

Water reducing admixtures are generally called by the name -----------

• Retarders

• plasticisers

• corrosion inhibitor

• pore filling admixtures

----- is not an effect of cold weather concreting

• Delay in setting and hardening.

• shrinkage cracks

• Freezing of concrete at early stage

• Freezing and thawing.

The ---------- underwater concreting is suitable for cases where a large mass of concrete is required for stabilizing foundations and small amount of concrete is needed for different locations.

• Hydro valve method

• Skip method

• Tilting pallet barge

• Pre-placed aggregate