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# Multiple choice question for engineering

## Set 1

1. How many principal thermal properties are there for aggregates?
a) 1
b) 2
c) 3
d) 4

Answer: c [Reason:] There are 3 principal thermal properties for aggregates: coefficient of thermal expansion, specific heat, thermal conductivity.

2. Coefficient of thermal expansion of concrete is ___ coefficient of thermal expansion in aggregates.
a) Directly proportional
b) Inversely proportional
c) Equal
d) More than

Answer: a [Reason:] Coefficient of thermal expansion of concrete increases with the increase in coefficient of thermal expansion of aggregates and vice-versa.

3. If the coefficient of thermal expansion of coarse aggregates and cement paste differs too much, then what happen?
a) A small change in temperature may introduce
b) No change
c) A large change in temperature may introduce
d) A small change in pressure may introduce

Answer: c [Reason:] If it happens then a large change in temperature may introduce differential movement which may break the bond between the aggregates and the paste.

4. If the coefficient of the two materials differ by more than 5.4 * 10-6 per oC, then
a) Workability of concrete may freeze
b) Durability of concrete subjected to freezing
c) Durability of concrete subjected to boiling
d) Workability of concrete subjected to boiling

Answer: b [Reason:] If the coefficient of the two materials differ by more than 5.4 * 10-6 per oC, then the Durability of concrete subjected to freezing and thawing may be affected.

5. For majority of aggregates, the coefficient of thermal expansion lies between approximately
a) 5.4 * 10-6 and 12.6 * 10-6 per oC
b) 10.8 * 10-6 and 16.2 * 10-6 per oC
c) 5.4 * 10-6 and 10.8 * 10-6 per oC
d) 10.8 * 10-6 and 12.6 * 10-6 per oC

Answer: a [Reason:] The coefficient of thermal expansion lies between approximately 5.4 * 10-6 and 12.6 * 10-6 per oC.

6. For hydrated Portland cement, the coefficient of thermal expansion lies between approximately
a) 5.4 * 10-6 and 12.6 * 10-6 per oC
b) 10.8 * 10-6 and 16.2 * 10-6 per oC
c) 5.4 * 10-6 and 10.8 * 10-6 per oC
d) 10.8 * 10-6 and 12.6 * 10-6 per oC

Answer: b [Reason:] The coefficient of thermal expansion for hydrated Portland cement lies between approximately 10.8 * 10-6 and 16.2 * 10-6 per oC.

7. The linear thermal coefficient of expansion lies between approximately
a) 5.4 * 10-6 and 12.6 * 10-6 per oC
b) 10.8 * 10-6 and 16.2 * 10-6 per oC
c) 5.8 * 10-6 and 14 * 10-6 per oC
d) 10.8 * 10-6 and 12.6 * 10-6 per oC

Answer: c [Reason:] The linear thermal coefficient of expansion lies between approximately 5.8 * 10-6 and 14 * 10-6 per oC depending upon the type of aggregates.

8. The specific heat of the aggregates is _____________
a) The ability to conduct the heat
b) The ability to insulate the heat
c) Is a measure of its heat capacity
d) Same as thermal conductivity

Answer: c [Reason:] The specific heat of the aggregates is a measure of its heat capacity and thermal conductivity is to conduct the heat.

9. The thermal conductivity of the aggregates is ______________
a) The ability to conduct the heat
b) The ability to insulate the heat
c) Is a measure of its heat capacity
d) Same as thermal conductivity

Answer: a [Reason:] Thermal conductivity is the ability of the aggregates to conduct the heat.

10. ”The coefficient of thermal expansion affects the heat resistance”. Is this statement true or false?
a) False
b) True

Answer: b [Reason:] Coefficient of thermal expansion and fire resistance both are related to the heat content.

## Set 2

1. Which chemical compostion has highest content in OPC?
a) Alumina
b) Silica
c) Lime
d) Iron Oxide

Answer: c [Reason:] Lime forms nearly two-third (2/3) of the cement. Therefore sufficient quantity of the lime must be in the raw materials for the manufacturing of cement.

2. Excess in lime causes ___
a) The cement to shrink and integrate
b) The cement to shrink and disintegrate
c) The cement to expand and integrate
d) The cement to expand and disintegrate

Answer: d [Reason:] Sufficient quantity of lime forms di-calcium silicate (C2SiO2) and tri-calcium silicate in the manufacturing of cement.

3. Silica in excess causes ____
a) The cement to set slowly
b) The cement to set quickly
c) The cement to expand
d) The cement to disintegrate

Answer: a [Reason:] Silica gives strength to the cement. Silica in excess causes the cement to set slowly.

4. Alumina in excess causes ____
a) Reduces the strength of the cement
b) Inceases the strength of the cement
c) No change
d) Sometimes increase or decrease the strength of the cement

Answer: a [Reason:] Alumina supports to set quickly to the cement. It also lowers the clinkering temperature. Alumina in excess, reduces the strength of the cement.

5. Which compound gives the colour to the cement?
a) Lime
b) Silica
c) Iron Oxide
d) Alumina

Answer: c [Reason:] Iron oxide pigments are in the form of particles ranging approximately from 0.1 to 1.0 micron. The difference in color between one pigment and another is due to the shape and surface structure of the particle.

6. Which cement contains high percentage of C3S and less percentage of C2S?
a) Rapid Hardening Cement
b) Ordinary Portland Cement
c) Quick Setting Cement
d) Low Heat Cement

Answer: a [Reason:] This cement contains high percentage of C3S and less percentage of C3S. This is infact high early strength cement.

7. When concrete is to be laid under water, ____ is to used.
a) Rapid Hardening Cement
b) Ordinary Portland Cement
c) Quick Setting Cement
d) Low Heat Cement

Answer: c [Reason:] When concrete is to be laid under water, quick setting cement is to used. This cement is manufactured by adding small percentage of aluminum sulphate (Al2SO4) which accelerates the setting action.

8. Which of the following is correct for Low Heat Cement?
a) Suitable for use in cold weather areas
b) Heat of hydration is reduced by tri calcium aluminate content
c) This cement requires longer period of curing
d) This cement contains high aluminate %age usually between 35-55%.

Answer: b [Reason:] In this cement the heat of hydration is reduced by tri calcium aluminate content. It contains less percentage of lime than ordinary port land cement. It is used for mass concrete works such as dams etc.

9. What is the percentage of iron oxide in white cement?
a) High
b) Very high
c) Medium
d) Very low

Answer: d [Reason:] As iron oxide gives the grey colour to cement, it is therefore necessary for white cement to keep the content of iron oxide as low as possible.

10. What is the percentage of air by volume in Air Entraining Cement?
a) 3-4
b) 10-11
c) 7-8
d) 9

Answer: a [Reason:] Entertainment of air also improves work ability and durability. It is recommended that air contents should be 03-04 % by volume.

## Set 3

1. What is plastic shrinkage?
a) It is not a result of any change in the concrete production process. Rather, it is a result of certain environmental conditions which occurs in the Central Missouri area
b) It is defined as the contracting of a hardened concrete mixture due to the loss of capillary water. This shrinkage causes an increase in tensile
c) It is an important phenomenon in young concrete. At low w/c ratios, less than about 0.42, all the water is rapidly drawn into the hydration process and the demand for more water creates very fine capillaries
d) It occurs when the concrete is exposed to air containing carbon dioxide

Answer: a [Reason:] It is not a result of any change in the concrete production process. Rather, it is a result of certain environmental conditions which occurs in the Central Missouri area.

2. How many types of shrinkages, caused due to loss of water?
a) 1
b) 2
c) 3
d) 4

Answer: c [Reason:] There are 3 types of shrinkage which are caused due to loss of water i.e. plastic, drying and autogenous.

3. How many types of shrinkages, caused due to cooling and carbonation?
a) 1
b) 2
c) 3
d) 4

Answer: b [Reason:] There are 2 types of shrinkage which are caused due to cooling and carbonation.

4. What is drying shrinkage?
a) It is not a result of any change in the concrete production process. Rather, it is a result of certain environmental conditions which frequently occur in the Central Missouri area
b) It is defined as the contracting of a hardened concrete mixture due to the loss of capillary water. This shrinkage causes an increase in tensile
c) It is an important phenomenon in young concrete. At low w/c ratios, less than about 0.42, all the water is rapidly drawn into the hydration process and the demand for more water creates very fine capillaries
d) It occurs when the concrete is exposed to air containing carbon dioxide

Answer: b [Reason:] It is defined as the contracting of a hardened concrete mixture due to the loss of capillary water. This shrinkage causes an increase in tensile.

5. What is autogenous shrinkage?
a) It is not a result of any change in the concrete production process. Rather, it is a result of certain environmental conditions which frequently occur in the Central Missouri area
b) It is defined as the contracting of a hardened concrete mixture due to the loss of capillary water. This shrinkage causes an increase in tensile
c) It is an important phenomenon in young concrete. At low w/c ratios, less than about 0.42, all the water is rapidly drawn into the hydration process and the demand for more water creates very fine capillaries
d) It occurs when the concrete is exposed to air containing carbon dioxide

Answer: c [Reason:] It is an important phenomenon in young concrete. At low w/c ratios, less than about 0.42, all the water is rapidly drawn into the hydration process and the demand for more water creates very fine capillaries.

6. What is carbonation shrinkage?
a) It is not a result of any change in the concrete production process. Rather, it is a result of certain environmental conditions which frequently occur in the Central Missouri area
b) It is defined as the contracting of a hardened concrete mixture due to the loss of capillary water. This shrinkage causes an increase in tensile
c) It is an important phenomenon in young concrete. At low w/c ratios, less than about 0.42, all the water is rapidly drawn into the hydration process and the demand for more water creates very fine capillaries
d) It occurs when the concrete is exposed to air containing carbon dioxide

Answer: d [Reason:] It occurs when the concrete is exposed to air containing carbon dioxide.

7. ACI 305.R.91 specifies Evaporation rate __ kg/hr/m2 should be avoided to prevent plastic cracking.
a) <.5
b) =0.5
c) >.5
d) Not equal to .5

Answer: c [Reason:] ACI 305.R.91 specifies Evaporation rate >0.5 kg/hr/m2 should be avoided to prevent plastic cracking.

8. Carbonic Acid + Ca(OH)2 ⇨ X. What is the main compound in X?
a) CaCO2
b) CO2
c) CaCO3
d) H2O

Answer: c [Reason:] It is a chemical reaction. It causes contraction of concrete which is known as Carbonation shrinkage.

9. If there is continuous supply of H2O to the concrete during hydration, concrete expands due to absorption of water by the cement gel. Is it true or false?
a) True
b) False

Answer: a [Reason:] If there is continuous supply of H2O to the concrete during hydration, concrete expands due to absorption of water by the cement gel and it is known as swelling.

10. Reduction in the volume due to shrinkage causes _____
a) Low volume
b) Volumetric strain
c) Volumetric stress
d) W/c ratio

Answer: b [Reason:] Reduction in the volume due to shrinkage causes volumetric strain in freshly hardened concrete.

## Set 4

1. Ultra-High Performance Concrete (UHPC), also known as ______
a) Active powder concrete
b) NPC
c) Reactive powder concrete
d) High Strength concrete

Answer: c [Reason:] Ultra-High Performance Concrete (UHPC), also known as reactive powder concrete (RPC), is a high-strength, ductile material.

2. The material used for UHPC provides compressive strengths up to __________
a) 17000 psi
b) 20000 psi
c) 25000 psi
d) 29000 psi

Answer: d [Reason:] The material provides compressive strengths up to 29000 pounds per square inch.

3. The material used for UHPC provides flexural strengths up to _________
a) 2000 psi
b) 5000 psi
c) 7000 psi
d) 10000 psi

Answer: c [Reason:] The material used for UHPC provides flexural strengths up to 7000 pounds per square inch.

4. Range of modulus of elasticity for UHPC ___________
a) 30-35 GPa
b) 35-40 GPa
c) 40-45 GPa
d) 45-50 GPa

Answer: d [Reason:] 45-50 GPa or 6500 to 7300 ksi is the range of modulus of elasticity for ultra-high performance concrete.

5. What is the compressive strength for UHPC?
a) 10-20 MPa
b) 60-100 MPa
c) 100-150 MPa
d) >150 MPa

Answer: c [Reason:] 28 days compressive strength for UHPC is 100-150MPa and for HPC, it’s 60-100 MPa.

6. “Where the matrix is extremely dense, a weak aggregate may become the weak”. Is this statement true or false?
a) True
b) False

Answer: a [Reason:] For very high-strength concrete where the matrix is extremely dense, a weak aggregate may become the weak link in concrete strength.

7. What is the percentage of water by weight in UHPC?
a) 28.5
b) 4.4
c) 1.2
d) 6.2

Answer: b [Reason:] 4.4 is the percentage of water by weight in UHPC according to typical composition of Ductal.

8. What is the percentage of PC by weight in UHPC?
a) 28.5
b) 4.4
c) 1.2
d) 6.2

Answer: a [Reason:] 28.5 is the percentage of PC by weight in UHPC according to typical composition of Ductal.

9. What is the percentage of steel fibre by weight in UHPC?
a) 28.5
b) 4.4
c) 1.2
d) 6.2

Answer: d [Reason:] 6.5 is the percentage of steel fibre by weight in UHPC according to typical composition of Ductal.

10. What is the percentage of accelerator by weight in UHPC?
a) 28.5
b) 4.4
c) 1.2
d) 6.2

Answer: c [Reason:] 1.2 is the percentage of accelerator by weight in UHPC according to typical composition of Ductal.

## Set 5

1. Which test is used to determine dimensions of any object?
a) Ultrasonic test
b) Torsion test
c) Eddy current test
d) Compression test

Answer: c [Reason:] Eddy current test is used to determine dimensions of objects, to detect cracks. An eddy current instrument consists of a probe or coil, an electronic unit for generating frequency and a CRT unit for display purpose.

2. Identify the type of destructive testing.
b) Dye penetrant test
c) Creep test
d) Visual testing

Answer: c [Reason:] Creep test is a type of destructive test. It is defined as slow plastic deformation at high temperatures for a longer time under constant stresses. Creep occurs at room temperature and at high temperatures.

3. Which test can be performed without skilled labor?
a) Probe test
b) Bend liquid test
c) Dye penetrant test
d) Torsion test

Answer: c [Reason:] Dye penetrant test does not require any skilled labor. This method only detects surface discontinuities and this test needs to be observed with naked eyes or with low magnifying glass.

4. Compressive strength of hardened concrete is done by _______
a) Cube test
b) Tensile splitting test
c) Concrete core test
d) Flexure test

Answer: a [Reason:] Compressive strength of hardened concrete is done by cube test. For cube test two types of specimens either cubes of 15cm X 15cm X 15cm or 10cm X 10cm x 10cm depending upon the size of aggregate are used.

5. In the soundness test a specimen of hardened cement paste is _______ for a fixed time.
a) Freeze
b) Dry
c) Boiled
d) Dipped in water

Answer: c [Reason:] A specimen of hardened cement paste is boiled for a fixed time so that if there is any tendency of increase or decrease in size can be detected.

6. Loss on Ignition (L.O.I.) is the loss in weight of cement after being heated to _______
a) 1000°C
b) 100°C
c) 500°C
d) 1500°C

Answer: a [Reason:] It indicates the prehydration or carbonation due to prolonged or improper storage of cement & clinker.

7. On cooling below 1250oC, C3S decomposes ______
a) Fast
b) Slowly
c) Never
d) Depends on the conditions

Answer: b [Reason:] On cooling below 1250oC, C3S decomposes slowly but, if cooling is not too slow, C3S remains unchanged and is relatively stable at ordinary temperatures.

8. What is final setting time?
a) The time at which cement paste loses its plasticity
b) The time to reach that stage at which cement paste loses its elasticity
c) The time at which cement paste gains its plasticity
d) The time when cement paste becomes hardened

Answer: a [Reason:] The final setting is defined as the time taken to reach the cement paste to become into a hardened mass.

9. The loss in weight should not exceed ______ percent when tested with sodium sulphate and ______ percent with magnesium sulphate solution.
a) 12, 18
b) 18, 12
c) 10, 15
d) 15, 10