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Concrete Technology Mcqs

Q:

Plasticizers are used in situations ___________

A) Where high degree of workability is required B) Where medium degree of workability is required
C) Where very low degree of workability is required D) Where low degree of workability is required
 
Answer & Explanation Answer: A) Where high degree of workability is required

Explanation: The decrease in the water/cement ratio enhances the concrete’s strength and longevity. Plasticizers are sometimes used in mass concrete to lower the cement content and hydration heat. Where low degree of workability is required like Deep beams, column and beam junctions.

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3405
Q:

Which of the following stress can Plain cement concrete endure?

A) Shear stress B) Tensile stress
C) Compressive stress D) Tensile, compressive, and shear stresses
 
Answer & Explanation Answer: C) Compressive stress

Explanation: Plain cement concrete is strong in taking compressive stress but weak in tensile stress. It consists of water, cement, coarse aggregate, and fine aggregate.

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284
Q:

Pick up the correct statement from the following.

A) Gypsum in cement decreases the setting time B) The first compound of cement which reacts with water is C?S
C) Bulking of sand is less when its particles are fine D) Dry process is less economically
 
Answer & Explanation Answer: A) Gypsum in cement decreases the setting time

Explanation: Any residual would have a negative effect on the setting. The gypsum should be mixed under vacuum, if possible, and to the exact water/powder ratio. The gypsum should be sprinkled into the water.

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277
Q:

During radiography test, which region absorbs less radiation and transmits more?

A) Low and high density regions absorb and transmit same amount of radiation B) High density region
C) Low density region D) Low and high density regions adsorb
 
Answer & Explanation Answer: C) Low density region

Explanation: This method uses short wavelength electromagnetic radiations such as X-rays and ? rays to detect internal defects. In this method the component to be tested is placed in path of radiations caused due to X-rays or ? rays.

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165
Q:

The density of concrete made with saturated aggregate is ___________

A) High B) Low
C) Very high D) Very low
 
Answer & Explanation Answer: A) High

Explanation: Moreover, the density of concrete made with saturated aggregate is higher and the durability of such concrete, especially its resistance to frost is lower.

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163
Q:

Approximate ratio of strength of the 30 cm cube to that of 15 cm cube is _____________

A) 1.1 B) 1
C) .9 D) .75
 
Answer & Explanation Answer: C) .9

Explanation: The strength of cylinder with diameter of 15cm and 30cm tall can be approximated as 0.84 of the strength of a 15x15x15 cm cube according to Eurocodes.

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161
Q:

Harshness in concrete is due to the excess of _____________

A) Water B) Finer particles
C) Middle sized particle D) Coarser particle
 
Answer & Explanation Answer: C) Middle sized particle

Explanation: It is the rough finishing property of concrete and causes improper proportioning, less compaction, low water content, excess of medium sized aggregates, deficiency of sand etc.

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151
Q:

When vibrators are used for compaction, the consistency of concrete depends upon the ___________

A) Type of mix B) Efficiency of vibrator
C) Placing conditions D) Type of mix, efficiency of vibrator, pacing conditions
 
Answer & Explanation Answer: D) Type of mix, efficiency of vibrator, pacing conditions

Explanation: When vibrators are used for compaction, the consistency of concrete depends upon the Type of mix, efficiency of vibrator, pacing conditions.

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