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430+ Concrete Technology Solved MCQs

These multiple-choice questions (MCQs) are designed to enhance your knowledge and understanding in the following areas: Civil Engineering .

351.

The most useless aggregate is, whose surface texture is

A. smooth
B. glossy
C. granular
D. porous
Answer» B. glossy
352.

High temperature

A. increases
B. decreases
Answer» B. decreases
353.

A suitable admixture added at the time of preparing the concrete mix, makes the concrete.

A. water proof
B. acid proof
C. highly strong
D. all of these
Answer» D. all of these
354.

A moist aggregate is one

A. whose all the pores are filled with water and also having its surface wet
B. whose all the pores are filled with water but having its surface dry
C. which do not contain any moisture either in the pores or on the surface
D. which may contain some moisture in the pores but having dry surface
Answer» A. whose all the pores are filled with water and also having its surface wet
355.

The finer the sand, greater is the bulkage.

A. Correct
B. Incorrect
Answer» A. Correct
356.

The fineness of cement is measured in terms of

A. percentage weight retained on IS sieve number 9
B. surface area in cm2 per gram of the cement
C. either (a) or (b)
D. none of these
Answer» C. either (a) or (b)
357.

For the manufacture of concrete of low density, the aggregate used is

A. furnace clinker
B. coke breeze
C. saw dust
D. all of these
Answer» D. all of these
358.

The value of bulk density of the aggregate depends upon

A. size distribution of aggregate
B. shape of aggregate
C. specific gravity of aggregate
D. all of these
Answer» D. all of these
359.

High percentage of tricalcium silicate and low percentage of dicalcium silicate in cement results in

A. rapid hardening
B. high erly strength
C. high heat generation
D. none of these
Answer» D. none of these
360.

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

A. type of mix
B. placing conditions
C. efficiency of vibrator
D. all of these
Answer» D. all of these
361.

Reinforced cement concrete is equally strong in taking

A. tensile and compressive stresses
B. compressive and shear stresses
C. tensile, compressive and shear stresses
D. tensile and shear stresses
Answer» C. tensile, compressive and shear stresses
362.

The process of mixing, transporting, placing and compacting the cement concrete should not take more than

A. 30 minutes
B. 60 minutes
C. 90 minutes
D. 120 minutes
Answer» A. 30 minutes
363.

The material having particle size varying from 0.002 to 0.06 mm is termed as

A. silt
B. clay
C. sand
D. none of these
Answer» A. silt
364.

The strength of cement concrete increases with the increase of water cement ratio.

A. Agree
B. Disagree
Answer» A. Agree
365.

The bulk density of aggregates depends upon its

A. shape
B. grading
C. compaction
D. all of these
Answer» D. all of these
366.

The main requirement, which a ware-house should fulfil is that

A. its walls should be water proof masonry construction
B. its roof should be leak-proof
C. it must have large number of windows
D. its plinth should be very high
E. Both (a) and (b)
Answer» E. Both (a) and (b)
367.

If the slump of the concrete mix is less than 50 mm, then while compacting it with vibratiors, the segregation will not take place.

A. Right
B. Wrong
Answer» A. Right
368.

The compressive strength of an ordinary Portland cement (1 : 3 cement mortar cube) after 7 days test should not be less than

A. 11 N/mm2
B. 17.5 N/mm2
C. 22 N/mm2
D. 27.5 N/mm2
Answer» B. 17.5 N/mm2
369.

If mineral oil is present in mixing water for concrete, it increases strength for a concentration upto 2 percent.

A. Yes
B. No
Answer» A. Yes
370.

Concrete with higher compaction factor has less workability.

A. True
B. False
Answer» A. True
371.

The aggregates of

A. irregular
B. angular
C. rounded
D. flaky
Answer» C. rounded
372.

The Indian standard code specifies that the crushing strength for which the mix should be designed in the laboratory should be

A. 1.25
B. 1.5
C. 2
D. 2.5
Answer» A. 1.25
373.

For batching 1 : 2 : 4 concrete mix by volume, the ingredients required per bag of cement are

A. 50 kg of cement : 70 kg of fine aggregate : 140 kg of coarse aggregate
B. 50 kg of cement : 70 litres of fine aggregate : 140 litres of coarse aggregate
C. 50 kg of cement : 100 kg of fine aggregate : 200 kg of coarse aggregate
D. 50 kg of cement : 100 litres of fine aggregate : 200 litres of coarse aggregate
Answer» B. 50 kg of cement : 70 litres of fine aggregate : 140 litres of coarse aggregate
374.

For heat and sound insulation purposes, we shall use

A. vacuum concrete
B. air-entrained concrete
C. saw dust concrete
D. both (b) and (c)
Answer» D. both (b) and (c)
375.

The strength and durability of concrete depends upon

A. size of aggregates
B. grading of aggregates
C. moisture contents of aggregates
D. all of these
Answer» D. all of these
376.

Which of the following statement is wrong?

A. The coarse sand produces a harsh and unworkable mix.
B. An admixture cannot increase the workability of concrete without increasing water content.
C. Salts of manganese cause a considerable reduction in the strength of concrete.
D. all of the above
Answer» B. An admixture cannot increase the workability of concrete without increasing water content.
377.

Insufficient quantity of water

A. makes the concrete mix harsh
B. makes the concrete mix unworkable
C. causes segregation in concrete
D. causes bleeding in concrete
Answer» B. makes the concrete mix unworkable
378.

In the manufacture of cement, the dry or wet mixture of calcareous and argillaceous materials is burnt at a temperature between

A. 900? to 1000?C
B. 1000?C to 1200?C
C. 1200?C to 1500?C
D. 1500?C to 1600?C
Answer» D. 1500?C to 1600?C
379.

The practical utility of concrete technology for civil engineers is to

A. enable them to know how to stock properly the materials required for concrete
B. enable them to perform different tests concerning concrete
C. make them conversant with fundamental principles of concrete
D. all of the above
Answer» D. all of the above
380.

Water-cement ratio is, usually, expressed in

A. litres of water required per bag of cement
B. litres of water required per kg of cement
C. both (a) and (b)
D. none of these
Answer» A. litres of water required per bag of cement
381.

With the moisture content of 5 to 10% by weight, the bulking of sand is increased by

A. 20%
B. 30%
C. 40%
D. 50%
Answer» D. 50%
382.

For continuous transportation of concrete, the method used is

A. transport of concrete by pans
B. transport of concrete by wheel barrows
C. transport of concrete by belt concrete conveyors
D. transport of concrete by pumps
Answer» C. transport of concrete by belt concrete conveyors
383.

Which of the following statement is correct?

A. Duff Abram's law is valid only when the concrete is of workable plasticity.
B. If the water-cement ratio is less, the strength of concrete will be less.
C. The strength of concrete decreases with age.
D. A rich mix of concrete provides low strength than a lean mix.
Answer» A. Duff Abram's law is valid only when the concrete is of workable plasticity.
384.

The function of aggregates in concrete is to serve as

A. binding material
B. filler
C. catalyst
D. all of these
Answer» B. filler
385.

The breaking up of cohesion in a mass of concrete is called

A. workability
B. bleeding
C. segregation
D. creep
Answer» C. segregation
386.

The Vee-Bee test is suitable for concrete mixes of low and very low workabilities.

A. True
B. False
Answer» A. True
387.

The aggregate which pass through 4.75 mm IS sieve and entirely retain on 75 micron IS sieve is called

A. cyclopean aggregate
B. coarse aggregate
C. fine aggregate
D. all-in-aggregate
Answer» C. fine aggregate
388.

Efflorescence in cement is caused due to the excess of

A. silica
B. lime
C. alkalies
D. iron oxide
Answer» C. alkalies
389.

Which of the following grade is not recommended by IS 456-1978?

A. M 10
B. M 20
C. M 40
D. M 55
Answer» D. M 55
390.

The deleterious materials present in the aggregate

A. prevent normal hydration of cement
B. reduce the strength and durability of concrete
C. modify the setting action and cause efflorescence
D. all of the above
Answer» D. all of the above
391.

Ferro-concrete is another name given to

A. plain cement concrete
B. reinforced cement concrete
C. prestressed cement concrete
D. none of these
Answer» B. reinforced cement concrete
392.

The use of air-entraining agents in concrete

A. increases workability of concrete
B. decreases bleeding
C. decreases strength
D. all of these
Answer» D. all of these
393.

The characteristic, which makes the concrete a versatile and widely used material of modern consturction, is the possibility of

A. controlling the properties of concrete by using appropriate ingredients
B. moulding the concrete in any desired shape
C. complete mechanisation of concrete preparation and its placing process
D. all of the above
Answer» D. all of the above
394.

The concrete in which no preliminary tests are performed for designing the mix is called

A. rich concrete
B. controlled concrete
C. lean concrete
D. ordinary concrete
Answer» D. ordinary concrete
395.

The cement concrete having water-cement ratio less than 0.45 by weight, causes honey-comb structure.

A. Correct
B. Incorrect
Answer» B. Incorrect
396.

The workability of concrete is defined as the

A. ease with which it can be mixed, transported and placed in position in a homogeneous state
B. breaking up of cohesion in a mass of concrete
C. separation of water or water-cement mixture from the freshly mixed concrete
D. none of the above
Answer» A. ease with which it can be mixed, transported and placed in position in a homogeneous state
397.

Low heat cement is used in

A. thin
B. thick
Answer» B. thick
398.

The removal of excess air after placing concrete helps in increasing the strength of concrete by

A. 15 to 20%
B. 20 to 30%
C. 30 to 50%
D. 50 to 70%
Answer» A. 15 to 20%
399.

In voids method of determining the quantity of cement paste, it is assumed that the

A. voids in the coarse aggregate are filled by the fine aggregates
B. volume of fine aggregates required for 1 m3 of coarse aggregate is equal to total voids in coarse aggregate plus 10% aggregate extra to allow for additional voids created by wedging action
C. volume of cement paste required for 1 m3 of coarse aggregate is equal to total volum of voids in the fine aggregate plus 15% aggregate extra to allow for additional voids created be wedging action
D. all of the above
Answer» D. all of the above
400.

The mass concrete in piers and abutments, the grade of concrete mix used, is

A. 1 ; 1 : 2
B. 1 ; 1.5 : 3
C. 1 ; 2 : 4
D. 1 ; 3 : 6
Answer» D. 1 ; 3 : 6

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