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Multiple choice question for engineering

Set 1

1. What is the gel/space ratio?
a) Volume of water to the volume of cement
b) Volume of the hydrated cement paste to the sum of volumes of the hydrated cement
c) Volume of the hydrated cement paste to the sum of volumes of the hydrated cement and of the capillary pores
d) Volume of gel to the volume of space present in concrete

View Answer

Answer: c [Reason:] This ratio is defined as the ratio of the volume of the hydrated cement paste to the sum of volumes of the hydrated cement and of the capillary pores.

2. Who has established the relation between the strength and gel/space ratio?
a) Abrams
b) Power
c) Brownyard
d) Power and Brownyard

View Answer

Answer: d [Reason:] Powers and Brownyard have established the relationship between the strength and gel/space ratio.

3. Power showed that the strength of concrete bears a specific relationship with the gel/space ratio. He found the relationship to be __________
a) 240x3
b) 140x3
c) 240x2
d) 140x2

View Answer

Answer: a [Reason:] Power’s experiment showed that the strength of concrete bears a specific relationship with the gel/space ratio. He found the relationship to be 240 x3.

4. What does 240 in power’s experiment stands for?
a) Gel space ratio
b) Water cement ratio
c) Intrinsic strength of gel
d) Extrinsic strength of gel

View Answer

Answer: c [Reason:] Power’s experiment showed that the strength of concrete bears a specific relationship with the gel/space ratio and the relationship comes to be 240 x3 where 240 represents the intrinsic strength of the gel.

5. What does x3 in power’s experiment stands for?
a) Gel space ratio
b) Water cement ratio
c) Intrinsic strength of gel
d) Extrinsic strength of gel

View Answer

Answer: a [Reason:] Power found the relationship to be 240 x3, where the value of x is the gel/space.

6. What unit is present with the 240?
a) Pa
b) MPa
c) GPa
d) KPa

View Answer

Answer: b [Reason:] During Power’s experiment, the intrinsic strength of the gel was comes out to be 240MPa.

7. Gel/Space ratio = x = Volume of gel / Space available = 0.657 C / 0.319 C+ Wo. Here C stands for?
a) Weight of cement in kg
b) Weight of cement in g
c) Volume of gel
d) Volume of mixing water in ml

View Answer

Answer: b [Reason:] According to Power and his experiment, the C is the weight of cement in grams.

8. Gel/Space ratio = x = Volume of gel / Space available = 0.657 C / 0.319 C+ Wo. Here Wo stands for?
a) Weight of cement in kg
b) Weight of cement in g
c) Volume of gel
d) Volume of mixing water in ml

View Answer

Answer: d [Reason:] According to Power and his experiment, Wo is the volume of mixing water in ml. concrete-technology-questions-answers-gel-space-ratio-q8

9. According to fig. what is the approx. value of strength of 50mm cube in MPa for gel-space ratio .6?
a) 20
b) 40
c) 60
d) 80

View Answer

Answer: b [Reason:] It is clearly seen from the fig that the corresponding value of strength for gel space ratio .6.

10. Referring to the graph below,what is the approx. value of strength of 50mm cube in MPa for gel-space ratio .8?
concrete-technology-questions-answers-gel-space-ratio-q10
a) 20
b) 40
c) 60
d) 80

View Answer

Answer: d [Reason:] It is clearly seen from the fig that the corresponding value of strength for gel space ratio .8.

Set 2

1. What could be the possible answer among the following for compressive strength of high strength concrete?
a) 10MPa
b) 20MPa
c) 30MPa
d) 40MPa

View Answer

Answer: d [Reason:] High strength of concrete has the compressive strength greater or equal to 40MPa.

2. What could be the possible answer among the following for water cement ratio for high strength concrete?
a) .5
b) .45
c) .4
d) .35

View Answer

Answer: d [Reason:] High strength of concrete made by lowering the water cement ratio nearly equal to 0.35 or less.

3. Due to low w/c ratio ___________
a) It doesn’t cause any problems
b) It causes problems
c) Workability is easy
d) Strength is more

View Answer

Answer: b [Reason:] Due to low water cement ratio, it causes problems so superplasticizers are used.

4. Which type of aggregates are used to produce 70MPa compressive strength?
a) All in one
b) Fine
c) Coarse
d) Flaky

View Answer

Answer: c [Reason:] To produce 70 MPa compressive strength, coarse aggregates are being used in HSC.

5. Maximum size of aggregates are used to produce 70MPa compressive strength is ________
a) 20-30 mm
b) 10-20 mm
c) 30-40 mm
d) 40-50 mm

View Answer

Answer: a [Reason:] Maximum size of aggregates is 20-30 mm are used to produce 70MPa compressive strength.

6. Maximum size of aggregates are used to produce 100MPa compressive strength is __________
a) 20-30 mm
b) 10-20 mm
c) 30-40 mm
d) 40-50 mm

View Answer

Answer: b [Reason:] Maximum size of aggregates is 10-20 mm are used to produce 100MPa compressive strength.

7. “In bridges, HSC is used”. Is it true or false?
a) True
b) False

View Answer

Answer: a [Reason:] In bridges, HSC is being used to reduce the number of beams for supporting span.

8. Use of HSC in column __________
a) It increase the size of the column
b) It decrease the size of the column
c) Doesn’t affect
d) Decrease the strength

View Answer

Answer: b [Reason:] Use of HSC in column section decreases the size of the column and used in high rise buildings.

9. Use of HSC in column ___________
a) Decrease the no of steel required in the same column
b) Increase the no of steel required in the same column
c) Decrease the no of steel required in the different column
d) Increase the no of steel required in the different column

View Answer

Answer: a [Reason:] Use of HSC in column, decrease the number of steel required in the same column.

10. High strength concrete is defined purely on the basis __________
a) Compressive strength
b) Poor strength
c) Tensile strength
d) Good strength

View Answer

Answer: a [Reason:] High strength concrete is defined purely on the basis of its compressive strength.

Set 3

1. It is ___________ strength and ___________ permeability.
a) High, high
b) Low, low
c) High, low
d) Low, high

View Answer

Answer: c [Reason:] It is specifically chosen so as to have particularly appropriate properties for the expected use of the structure such as high strength and low permeability.

2. “High Performance concrete works out to be economical”. Is it true or false?
a) True
b) False

View Answer

Answer: a [Reason:] High Performance concrete works out to be economical, even though its initial cost is high.

3. “HPC is not used in high span bridges”. Is it true or false?
a) True
b) False

View Answer

Answer: b [Reason:] Major applications of high-performance concrete in the field of Civil Engineering constructions have been in the areas of long-span bridges, high-rise buildings or structures, highway pavements, etc.

4. Concrete having 28- days’ compressive strength in the range of 60 to 100 MPa.
a) HPC
b) VHPC
c) OPC
d) HSC

View Answer

Answer: a [Reason:] High Performance Concrete having 28- days’ compressive strength in the range of 60 to 100 MPa.

5. Concrete having 28-days compressive strength in the range of 100 to 150 MPa.
a) HPC
b) VHPC
c) OPC
d) HSC

View Answer

Answer: b [Reason:] Very high performing Concrete having 28-days compressive strength in the range of 100 to 150 MPa.

6. High-Performance Concrete is ____________ as compared to Normal Strength Concrete.
a) Less brittle
b) Brittle
c) More brittle
d) Highly ductile

View Answer

Answer: c [Reason:] High-Performance Concrete is more brittle as compared to Normal Strength Concrete (NSC), especially when high strength is the main criteria.

7. The choice of cement for high-strength concrete should not be based only on mortar-cube tests but it should also include tests of compressive strengths of concrete at ___________ days.
a) 28, 56, 91
b) 28, 60, 90
c) 30, 60, 90
d) 30, 45, 60

View Answer

Answer: a [Reason:] The choice of cement for high-strength concrete should not be based only on mortar-cube tests but it should also include tests of compressive strengths of concrete at 28, 56, and 91 days.

8. For high-strength concrete, a cement should produce a minimum 7-days mortar-cube strength of approximately ___ MPa.
a) 10
b) 20
c) 30
d) 40

View Answer

Answer: c [Reason:] For high-strength concrete, a cement should produce a minimum 7-days mortar-cube strength of approximately 30 MPa.

9. ____________ mm nominal maximum size aggregates gives optimum strength.
a) 9.5 and 10.5
b) 10.5 and 12.5
c) 9.5 and 12.5
d) 11.5 and 12.5

View Answer

Answer: c [Reason:] Many studies have found that 9.5 mm to 12.5 mm nominal maximum size aggregates gives optimum strength.

10. Due to low w/c ratio
a) It doesn’t cause any problems
b) It causes problems
c) Workability is easy
d) Strength is more

View Answer

Answer: b [Reason:] Due to low w/c ratio, it causes problems so superplasticizers are used.

Set 4

1. What is hydration of cement?
a) Chemical reaction of cement with acid
b) Chemical reaction of cement with water
c) Chemical reaction of cement with base
d) Chemical reaction of cement with salt, and acid

View Answer

Answer: b [Reason:] As water comes into contact with cement particles, hydration reactions immediately starts at the surface of the particles.

2. As the hydration proceeds the deposits of hydrated products on the original cement grains makes the diffusion of water to unhydrated nucleus ____
a) Easy
b) Very difficult
c) Very easy
d) Average

View Answer

Answer: b [Reason:] It is difficult thus the rate of hydration decreases with time & as a result hydration may take several years.

3. The development of first 28 days strength is on account of the hydration of __
a) C2S
b) C3S
c) C3A
d) C4AF

View Answer

Answer: b [Reason:] Higher C3S→higher early strength-higher heat generation (roads, cold environments). Higher CS→lower early strength-lower heat generation (dams).

4. Which compound is liberates higher heat?
a) C2S
b) C3S
c) C3A
d) C4AF

View Answer

Answer: b [Reason:] C3S having a faster rate of reaction accompanied by greater heat generation developes early strength of the paste.

5. Which compound is liberates lower heat?
a) C2S
b) C3S
c) C3A
d) C4AF

View Answer

Answer: a [Reason:] C2S hydrates & hardens slowly so results in less heat generation & developes most of the ultimate strength.

6. Which compound may lead to a rapid stiffening of the paste with a large amount of the heat generation?
a) C2S
b) C3S
c) C3A
d) C4AF

View Answer

Answer: c [Reason:] C3A is characteristically fast reacting with water & may lead to a rapid stiffening of the paste with a large amount of the heat generation (Flash-Set)-(Quick-Set).

7. In order to prevent this rapid reaction ___ is added to the clinker.
a) C4AF
b) Gypsum
c) Water
d) Extra cement

View Answer

Answer: b [Reason:] In order to prevent this rapid reaction gypsum is added to the clinker. Gypsum, C3A&water react to form relatively insoluble Calcium-Sulfo-Aluminates.

8. For complete hydration of cement the w/c ratio needed is ____
a) More than 0.25
b) More than 0.25 but less than 0.35
c) More than 0.35 but less than 0.60
d) More than 0.60

View Answer

Answer: c [Reason:] A mix with a ratio of 0.45 may not mix thoroughly, and may not flow well enough to be placed. More water is therefore used than is technically necessary to react with cement. Water–cement ratios of 0.45 to 0.60 are more typically used.

9. The minimum water to cement ratio for cement concrete to hydrate is ___
a) 0.65
b) 0.5
c) 0.38
d) 0.27

View Answer

Answer: c [Reason:] Minimum water cement ratio is 0.38. It cannot be 35 kg. W/C ratio depends on the exposure condition of concrete but minimum water cement ratio is 0.38 for full hydration of concrete.

10. Approximate percentage range of A2O3 in OPC is ___
a) 17-25
b) 3-8
c) 3- 10
d) 4-15

View Answer

Answer: c [Reason:] Percentage of A2O3 is 3-8, CaO has 60-67, SiO2 has 17-25, SO3 is 1-3, MgO has .1-4 and soda has .5-1.3.

Set 5

1. When the cement paste is tested within the gauging time. Here what is the value of gauging time?
a) 3 to 5 minutes
b) 3 to 5 hours
c) 24 minutes
d) 24 hours

View Answer

Answer: a [Reason:] When the cement paste is tested within the gauging time ( 3 to 5 minutes) after the cement is thoroughly mixed with water.

2. A maximum value of ___ percent is allowed for WBM base course in Indian conditions.
a) 25
b) 35
c) 40
d) 50

View Answer

Answer: c Answer: A maximum value of 40 percentage is allowed for Water Bound Macadam base course in Indian conditions.

3. Which machine is preferred for abrasion test?
a) Vicat’s mould
b) Los Angeles
c) Flakiness Gauge
d) Elongation Gauge

View Answer

Answer: b [Reason:] Los Angeles is preffered for abrasion test for carrying out the hardness property and has been standardized in India.

4. The mineral oil if present in mixing for concrete ______________
a) Improves strength
b) Reduces strength
c) Gives more slump
d) Gives a smooth surface

View Answer

Answer: a [Reason:] The mineral oil if present in mixing for concrete increases strength for the concentration up to 2%.

5. With regard to the curing water, identify the incorrect statement.
a) Curing water shouldn’t produce objectionable stains on the surface
b) The presence of tannic acid and iron compounds is objectionable
c) Iron and organic matter are responsible for staining
d) Water is suitable for mixing is also suitable for curing

View Answer

Answer: c [Reason:] With regard to the curing water, Iron and organic matter are responsible for staining.

6. To neutralize 200 ml of sample should not require more than 10 ml of __ normal HCI using methyl orange.
a) 1
b) .1
c) 10
d) .01

View Answer

Answer: b [Reason:] To neutralize 200 ml of water sample the value of 0.1 normal HCI using methyl orange as an indicator should not require more than 10 ml.

7. Aggregates to be used for wearing course, the impact value shouldn’t exceed __ percent.
a) 30
b) 35
c) 40
d) 25

View Answer

Answer: a [Reason:] Aggregates to be used for wearing course, the impact value shouldn’t exceed 30 %. For bituminous macadam the maximum permissible value is 35 %.

8. What is the range of water absorption of aggregates used in road?
a) 2.5-2.9
b) .1-2
c) .1-2.5
d) 2-2.9

View Answer

Answer: b [Reason:] The specific gravity of aggregates normally used in road ranges from about 2.5 to 2.9. Water absorption values ranges from 0.1 to about 2.0 percent for aggregates normally used in road surfacing.

9. The loss in weight should not exceed __ % when tested with Na2SO4 and __ % with MgSO4 solution.
a) 12, 18
b) 18, 12
c) 10, 15
d) 15, 10

View Answer

Answer: a [Reason:] The loss in weight should not exceed 12 percent when tested with sodium sulphate and 18 percent with magnesium sulphate solution.

10. If 60% aggregates doesn’t pass through the 2.36mm sieve, then what would be the value of Aggregate impact value?
a) 60%
b) 40%
c) 25%
d) 100%

View Answer

Answer: b [Reason:] Aggregate impact value = (W1/W2)*100 = {(100-60)/100} * 100 = 40%