430+ Concrete Technology Solved MCQs

1.

Processes of cement manufacturing is…….?

A. Wet process
B. Dry process
C. Semi-dry process
D. All of above
Answer» D. All of above
2.

After 28 days of curing, cement gains have been found to have hydrated to a depth of only…..u.

A. 2
B. 3
C. 4
D. 6
Answer» C. 4
3.

Total…….. % of water by weight of water by weight of cement is required for complete hydration.

A. 40
B. 38
C. 42
D. 50
Answer» B. 38
4.

Hydration of cement is due to chemical action of water with

A. Tricalcium silicate and dicalcium silicate
B. Dicalcium silicate and tricalcium aluminate
C. Tricalcium aluminate and tricalcium alumino ferrite
D. All the above.
Answer» D. All the above.
5.

Proper proportioning of concrete, ensures

A. desired strength and workability
B. desired durability
C. water tightness of the structure
D. all the above
Answer» D. all the above
6.

An aggregate is said to be flaky if its least dimension is less than

A. 1/5th of mean dimension
B. 2/5th of mean dimension
C. 3/5th of mean dimension
D. 4/5th of mean dimension
Answer» C. 3/5th of mean dimension
7.

A small quantity of …………. % of gypsum is added to prevent flash-setting of the cement.

A. 1 to 2
B. 2 to 3
C. 9 to 10
D. 10 to 12
Answer» B. 2 to 3
8.

Highest oxide composition present in cement is……

A. Silica
B. Alumina
C. Iron oxides
D. Lime
Answer» D. Lime
9.

First 7 days strength in cement is due to….. Bogue compound.

A. C3S
B. C2S
C. C3A
D. C4AF
Answer» A. C3S
10.

Heat of hydration of C3S at 90 days is ………. cal/g

A. 58
B. 104
C. 122
D. 150
Answer» B. 104
11.

…………refers to the gain of strength of a set cement paste.

A. Setting of cement
B. Hardening of cement
C. none
D. all
Answer» B. Hardening of cement
12.

For long time storage ……..cement used.

A. Masonry cement
B. Ordinary
C. Hydrophobic
D. All of above
Answer» C. Hydrophobic
13.

Repair of air-field pavement use……

A. Air entrained cement
B. Very high Strength cement
C. Rediset Cement
D. All of above
Answer» B. Very high Strength cement
14.

Note more than ……. bags should be kept one above other.

A. 20
B. 25
C. 14
D. Any of above
Answer» C. 14
15.

For Fineness test ……. micron sieve is use.

A. 100
B. 80
C. 60
D. 90
Answer» D. 90
16.

The weight of residue should not exceed ……. for OPC.

A. 10 %
B. 20 %
C. 30%
D. 40%
Answer» A. 10 %
17.

For consistency test vicat plunger having ……. dia and …….. Length is used.

A. 15 mm & 45 mm
B. 10 mm & 50 mm
C. 20 mm & 60mm
D. Any of above
Answer» B. 10 mm & 50 mm
18.

For OPC Value of IST And FST is…… .

A. 30 m & 600 m
B. 50 m & 700 m
C. 20m & 500 m
D. 40m & 800 m
Answer» A. 30 m & 600 m
19.

For compressive strength test of cement ………. water is added.

A. p/3 + 3
B. p/2 + 3
C. p/4 + 3
D. p/5 +3
Answer» C. p/4 + 3
20.

Undesirable expansion of some of constituents of cement after setting is known as……… .

A. Soundness
B. unsoundness
C. none
D. all
Answer» B. unsoundness
21.

Density of light weight aggregate concrete is about …….. kg/m3 .

A. 3000
B. 1500
C. 1200
D. 1400
Answer» C. 1200
22.

Material between…………… is classified as silt.

A. 002 mm to 0.003 mm
B. 0.08 mm to 1 mm
C. 8 mm to 10 mm
D. 0.06 mm to 0.002 mm
Answer» D. 0.06 mm to 0.002 mm
23.

Angular aggregate having percentage of voids ranging from……….

A. 32 to 33
B. 35 to 38
C. 38 to 40
D. 40 to 45
Answer» C. 38 to 40
24.

In crushing value test of aggregate, gradually compressive load of….. Tons is apply.

A. 40
B. 50
C. 44
D. 45
Answer» A. 40
25.

Specific gravity of natural aggregate lie between……

A. 2.5 to 2.6
B. 2.6 to 2.7
C. 2.6 to 2.8
D. 2.8 to 2.9
Answer» C. 2.6 to 2.8
26.

Coarse aggregates absorbs…….. % of moisture.

A. 1 to 2
B. 0.5 to 1
C. 2 to 4
D. 2 to 3
Answer» B. 0.5 to 1
27.

To control alkali aggregate reaction restricting alkali content in cement below……%

A. 1
B. 0.1
C. 0.5
D. 0.6
Answer» D. 0.6
28.

If the actual grading curve is steeper than the specified grading curve, it indicates an excess of ……..particle size.

A. sand
B. coarser
C. medium
D. cement
Answer» C. medium
29.

Fineness modulus of fine sand is…… .

A. 2.2 – 2.6
B. 2.6 – 2.9
C. 2.9 – 3.2
D. 3.2 - 4.2
Answer» A. 2.2 – 2.6
30.

Permissible limit organic solids in water is……..mg/l

A. 400
B. 600
C. 200
D. 500
Answer» C. 200
31.

Bigger size of aggregate will give higher workability.

A. True
B. False
C. none
D. all
Answer» A. True
32.

To measure workability of concrete in field …………….test is used.

A. Flow test
B. Compacting factor test
C. Slump test
D. All of above
Answer» C. Slump test
33.

Steel tamping rod of 0.6m length and 16 mm diameter is used for tamping of concrete.

A. False
B. True
C. none
D. all
Answer» B. True
34.

Types of slump is…..

A. True slump
B. Shear slump
C. Collapse slump
D. All of above
Answer» D. All of above
35.

25 to 75 mm workability of concrete, indicate

A. High workability
B. Medium workability
C. Low workability
D. Any of this
Answer» C. Low workability
36.

In very low category of degree of workability determination by compacting factor will be more appropriate.

A. True
B. False
C. none
D. all
Answer» A. True
37.

Compacting factor test should be made for concrete with maximum size of aggregate not exceeding 40 mm.

A. True
B. False
C. none
D. all
Answer» A. True
38.

The value of flow % may range anything from 0 to …. %

A. 200
B. 250
C. 210
D. 150
Answer» D. 150
39.

Separating out of the ingredients of concrete mix from concrete is known as……… .

A. Segregation
B. bleeding
C. separation
D. Any of these
Answer» A. Segregation
40.

Water from concrete comes out to the surface of the concrete is known as……….

A. Segregation
B. bleeding
C. separation
D. Any of these
Answer» B. bleeding
41.

Main causes of bleeding :

A. Highly wet mix
B. Badly proportion mix
C. Insufficiently mixed concrete
D. All of this
Answer» D. All of this
42.

The formation of cement paste at the surface is known as laitance.

A. True
B. False
C. none
D. all
Answer» A. True
43.

Workability of concrete is……. to the w/c.

A. proportional
B. inversely proportional
C. none
D. all
Answer» A. proportional
44.

Workability of concrete is …….to the strength of concrete.

A. proportional
B. inversely proportional
C. none
D. all
Answer» B. inversely proportional
45.

Good method for proportioning the materials.

A. Weight batching
B. Volume batching
C. none
D. all
Answer» A. Weight batching
46.

In Volume batching 1 bag cement =

A. 35 lit
B. 40 lit
C. 45 lit
D. 50 lit
Answer» A. 35 lit
47.

In volume batching………. % of bulking is take into account.

A. 30
B. 40
C. 20
D. 10
Answer» C. 20
48.

Density of water is 1 kg/liter.

A. True
B. false
C. none
D. all
Answer» A. True
49.

In hand mixing …….. % more cement is added in mix.

A. 30
B. 40
C. 20
D. 10
Answer» D. 10
50.

Concrete mixer are generally designed to run at a speed of ……….. Revolution per minute.

A. 40 to 50
B. 30 to 40
C. 15 to 20
D. 20 to 30
Answer» C. 15 to 20
51.

For proper mixing about…………. revolution are required.

A. 40 to 50
B. 30 to 40
C. 15 to 20
D. 25 to 30
Answer» D. 25 to 30
52.

The process of mixing, transporting, placing and compacting concrete should not take more than ……. min any case.

A. 90
B. 80
C. 70
D. 60
Answer» A. 90
53.

Commonly use retarders is……

A. Calcium sulphate
B. Sugars
C. Cellulose products.
D. All of the above
Answer» D. All of the above
54.

Inert material of a cement concrete mix, is

A. water
B. cement
C. aggregate
D. none of these
Answer» C. aggregate
55.

Placing of concrete should preferably be done at a temperature of

A. 0°C
B. 10°C
C. 20°C
D. 27 ± 2°C
Answer» D. 27 ± 2°C
56.

The aggregate impact value of the aggregate used in

A. building concrete is less than 45
B. road pavement concrete is less than 30
C. runway concrete is less than 30
D. all the above.
Answer» D. all the above.
57.

On a grading curve, the gap grading is represented by

A. a horizontal line
B. a vertical line
C. N.W. inclined line
D. N.E. inclined line
Answer» A. a horizontal line
58.

Bulking of sand is

A. mixing of different sizes of sand particles
B. mixing of lime with sand
C. maximum water with sand
D. swelling of sand when wetted
Answer» D. swelling of sand when wetted
59.

Curing of pavements, floors, roofs and slabs, is done by

A. membrane method
B. ponding method
C. covering surface with bags
D. sprinkling water method
Answer» B. ponding method
60.

Pick up the incorrect statement from the following:

A. With passage of time, the strength of cement increases
B. With passage of time, the strength of cement decreases
C. After a period of 24 months, the strength of cement reduces to 50%
D. The concrete made with storage deteriorated cement, gains strength with time
Answer» A. With passage of time, the strength of cement increases
61.

The surface where two successive placements of concrete meet, is known as

A. Contraction joint
B. Expansion joint
C. Construction joint
D. both (a) and (b)
Answer» C. Construction joint
62.

An excess of flaky particles in concrete aggregates

A. decreases the workability
B. increases the quantity of water and sand
C. affects the durability of concrete
D. all the above
Answer» D. all the above
63.

I.S.I. has specified the full strength of concrete after

A. 7 days
B. 14 days
C. 21 days
D. 28 days
Answer» D. 28 days
64.

The minimum percentage of chemical ingredient of cement is that of

A. magnesium oxide
B. iron oxide
C. alumina
D. lime
Answer» A. magnesium oxide
65.

The specifications of a cement bag for storage, are

A. weight 50 kg
B. height 18 cm
C. plan area 3000 sq. cm
D. all the above
Answer» D. all the above
66.

The bulk density of aggregates, depends upon

A. shape
B. grading
C. compaction
D. all the above.
Answer» D. all the above.
67.

The concrete mix which causes difficulty in obtaining a smooth finish, possess

A. segregation
B. internal friction
C. harshness
D. bleeding
Answer» C. harshness
68.

An aggregate is known as cyclopean aggregate if its size is more than

A. 4.75 mm
B. 30 mm
C. 60 mm
D. 75 mm
Answer» D. 75 mm
69.

The main object of compaction of concrete, is:

A. to eliminate air holes
B. to achieve maximum density
C. to provide intimate contact between the concrete and embedded materials
D. all the above
Answer» D. all the above
70.

Concrete gains strength due to

A. chemical reaction of cement with sand and coarse aggregates
B. evaporation of water from concrete
C. hydration of cement
D. All the above
Answer» C. hydration of cement
71.

If aggregates completely pass through a sieve of size 75 mm and are retained on a sieve of size 60 mm, the particular aggregate will be flaky if its minimum dimension is less than

A. 20.5 mm
B. 30.5 mm
C. 40.5 mm
D. 50.5 mm
Answer» C. 40.5 mm
72.

Log Angles machine is used to test the aggregate for

A. crushing strength
B. impact value
C. abrasion resistance
D. water absorption
Answer» C. abrasion resistance
73.

Pozzolanic properties exist in

A. shales
B. fly ash
C. pumicite
D. all the above
Answer» D. all the above
74.

Workability improved by adding

A. fly ash
B. hydrated lime
C. calcium chloride
D. all the above
Answer» D. all the above
75.

If the various concrete ingredients i.e. cement, sand and aggregates are in the ratio of 1:3:6, the grade of concrete, is

A. M 10
B. M 15
C. M 20
D. M 30
Answer» A. M 10
76.

Gypsum is added for

A. colour
B. strength
C. controlling setting time
D. none of these
Answer» C. controlling setting time
77.

Cement used for normal concrete construction, is obtained by burning a mixture of

A. silicious and argillaceous materials
B. argilaceous and calcareous materials
C. silicious and catcareous materials
D. silicious, argillaceous and calcareous materials
Answer» D. silicious, argillaceous and calcareous materials
78.

In slump test, each layer of concrete is compacted by a steel rod 60 cm long and of 16 mm diameter for

A. 20 times
B. 25 times
C. 30 times
D. 40 times
Answer» B. 25 times
79.

Efflorescence in cement is caused due to an excess of

A. alumina
B. iron oxide
C. silica
D. alkalis
Answer» D. alkalis
80.

Slump test of concrete is a measure of its

A. consistency
B. compressive strength
C. tensile strength
D. impact value.
Answer» A. consistency
81.

Pick up the incorrect statement applicable to the field test of good cement.

A. When one thrusts one's hand into a bag of cement, one should feel warm
B. The colour of the cement is bluish
C. A handful of cement thrown into a bucket of water should sink immediately
D. All the above
Answer» D. All the above
82.

The most useless aggregate is one whose surface texture is

A. smooth
B. granular
C. glassy
D. honey combed and porous
Answer» C. glassy
83.

The top diameter, bottom diameter and the height of a slump mould are :

A. 10 cm, 20 cm, 30 cm
B. 10 cm, 30 cm, 20 cm
C. 20 cm, 10 cm, 30 cm
D. 20 cm, 30 cm, 10 cm
Answer» A. 10 cm, 20 cm, 30 cm
84.

For concreting tunnel linings, transportation of concrete is done by

A. pans
B. wheel borrows
C. containers
D. pumps
Answer» D. pumps
85.

Admixture which cause early setting and hardening of concrete are called …

A. Workability admixtures
B. accelerators
C. retarders
D. air entraining agents
Answer» B. accelerators
86.

As compared to ordinary Portland cement, high alumina cement has

A. higher initial setting time but lower final setting time
B. lower initial setting time but higher final setting time
C. none
D. all
Answer» A. higher initial setting time but lower final setting time
87.

Maximum permissible limit of magnesia content in OPC is…

A. 4 %
B. 6%
C. 8%
D. 10%
Answer» B. 6%
88.

Reduction in the quantity of mixing water which is possible by the use of plasticizers and admixture varies from

A. 1% to 5%
B. 5% to 15%
C. 15% to 25%
D. 25% to 35%
Answer» B. 5% to 15%
89.

Which of the following types of concrete mixture is most commonly used in precast concrete factories?

A. truck mounted mixture
B. pan type mixer
C. dual drum mixture
D. tilting drum mixture
Answer» B. pan type mixer
90.

According to IS : 456-1978 minimum period stipulated for most curing of concrete using ordinary Portland cement is

A. 3 days
B. 7 days
C. 14 days
D. 28 days
Answer» B. 7 days
91.

For reinforced concrete exposed to sulphate attack minimum grade required is

A. M10
B. M15
C. M20
D. M25
Answer» C. M20
92.

The deterioration of concrete take place due to.

A. Salt solution
B. Alkalies
C. Fertilizers
D. All of the above
Answer» D. All of the above
93.

Cement content should be such that concrete has sufficient alkalinity (PH value).

A. True
B. False
C. none
D. all
Answer» A. True
94.

For sea water concreting …………. cement shall be used.

A. Portland slag cement
B. Portland pozzolana slag cement
C. Super sulphated cement
D. All of above
Answer» D. All of above
95.

Durability of concrete can be improved by impregnation of …………… in the voids of concrete.

A. polymer
B. cement
C. Lime
D. Soda
Answer» A. polymer
96.

What do you mean by admixtures?

A. Ingredients which are added to in cement before or after concrete mix
B. Ingredients which are added to make aggregates healthier
C. Ingredients added in cement to make it shinier
D. Ingredients added in concrete to make good workability
Answer» A. Ingredients which are added to in cement before or after concrete mix
97.

Super plasticizers reduce water requirement by ___________ %.

A. 12-30
B. 10-15
C. 30-42
D. 48
Answer» A. 12-30
98.

Damp proofing is done with a __________ based mixture.

A. Sand
B. Tar
C. Rubber
D. Lead
Answer» B. Tar
99.

What is water proofing admixtures?

A. Water repellent materials
B. Water fair material
C. Water absorption material
D. Water adsorption material
Answer» A. Water repellent materials
100.

Which one is not a chemically active pore filling material?

A. Silicate of soda
B. Aluminium
C. Chalk
D. Zinc
Answer» B. Aluminium
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