Floating Concrete III Year
Questions and Answers
- 1.
Blaines air permeability method is used to determine
- A.
Permeability of cement
- B.
Fineness of cement
- C.
Soundness of cement
- D.
Remoulding effect
Correct Answer
B. Fineness of cementExplanation
Blaine's air permeability method is a widely accepted test method used to determine the fineness of cement. The test involves measuring the rate at which air passes through a compacted bed of cement particles under specific conditions. The higher the permeability, the finer the cement particles. This method is important because the fineness of cement affects its hydration rate, workability, and strength development. Therefore, Blaine's air permeability method is specifically designed to assess the fineness of cement.Rate this question:
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- 2.
Vee-Bee consistency test is carried out to measure
- A.
Permeability of cement
- B.
Fineness of cement
- C.
Setting time of cement
- D.
Remoulding effect
Correct Answer
D. Remoulding effectExplanation
The Vee-Bee consistency test is conducted to measure the remoulding effect of cement. This test determines the ability of cement paste to flow under vibration, indicating its workability. It measures the time taken for the cement paste to reach a particular degree of consistency, which is influenced by factors like water content, cement particle size, and chemical admixtures. Therefore, the Vee-Bee consistency test helps in assessing the ease of handling and placing the cement paste during construction activities.Rate this question:
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- 3.
Properly ground cement should have an specific surface of
- A.
1500 sq. cm per gram
- B.
2000 sq. cm per gram
- C.
2250 sq. cm per gram
- D.
2450 sq. cm per gram
Correct Answer
C. 2250 sq. cm per gramExplanation
The specific surface of cement refers to the total surface area of the cement particles per unit mass. A higher specific surface indicates that the cement particles are more finely ground and have a larger surface area available for chemical reactions. In this case, a specific surface of 2250 sq. cm per gram indicates that the cement is finely ground and has a large surface area, making it suitable for use in construction applications.Rate this question:
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- 4.
Quick setting cement is used
- A.
Under running water
- B.
In mass concrete
- C.
For interior decoration
- D.
To impart architectural finish
Correct Answer
A. Under running waterExplanation
Quick setting cement is used under running water because it has the property of setting rapidly even in the presence of water. This makes it suitable for applications where water cannot be completely avoided, such as underwater repairs, fixing leaks in pipes, or setting concrete in wet conditions. The quick setting nature of this cement allows it to harden and provide strength within a short period of time, even when exposed to water, ensuring that the desired results are achieved efficiently.Rate this question:
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- 5.
Quick setting cement contains a higher percentage of
- A.
Silicate
- B.
Sulphate
- C.
Lime
- D.
Alumina
Correct Answer
D. AluminaExplanation
Quick setting cement contains a higher percentage of alumina. Alumina is a compound that is commonly used in cement production as it helps to increase the setting time of the cement. It also improves the strength and durability of the cement. By having a higher percentage of alumina, quick setting cement can set faster and provide a stronger final product.Rate this question:
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- 6.
Quick setting cement hardens in
- A.
5 minutes
- B.
15 minutes
- C.
30 minutes
- D.
2 hours
Correct Answer
C. 30 minutesExplanation
Quick setting cement typically hardens and sets in a relatively short amount of time compared to regular cement. In this case, the correct answer is 30 minutes, which means that after the cement is mixed and applied, it will start to harden and become solid within half an hour. This quick setting time makes it suitable for applications where a fast turnaround or quick repairs are required, such as patching holes or setting posts.Rate this question:
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- 7.
Low heat cement contains lower percentage of
- A.
C3A
- B.
C3S
- C.
Both (a) and (b)
- D.
Neither (a) nor (b)
Correct Answer
C. Both (a) and (b)Explanation
Low heat cement contains a lower percentage of both C3A and C3S. C3A (tricalcium aluminate) and C3S (tricalcium silicate) are the main compounds found in cement. C3A is responsible for the early strength development of cement, but it also generates more heat during the hydration process. C3S contributes to the long-term strength of cement. By reducing the percentage of both C3A and C3S, low heat cement is designed to produce less heat during hydration, making it suitable for projects where heat generation needs to be minimized, such as large concrete structures or mass concrete pours.Rate this question:
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- 8.
Low heat cement contains higher percentage of
- A.
C2S
- B.
C3S
- C.
Both (a) and (b)
- D.
Neither (a) nor (b)
Correct Answer
D. Neither (a) nor (b)Explanation
Low heat cement contains a lower percentage of C2S and C3S compared to regular cement. C2S and C3S are the main compounds responsible for the strength development in cement. However, in low heat cement, the reduction in these compounds helps to reduce the heat generated during hydration, making it suitable for large concrete structures where heat build-up can cause cracking. Therefore, the correct answer is neither (a) nor (b) as low heat cement contains a lower percentage of both C2S and C3S.Rate this question:
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- 9.
Low heat cement is used in
- A.
RCC slabs
- B.
Columns
- C.
Dams
- D.
Tunnels
Correct Answer
C. DamsExplanation
Low heat cement is used in dams because dams require large concrete structures that generate a significant amount of heat during the curing process. Low heat cement is specially designed to reduce the heat of hydration, preventing thermal cracking and ensuring the structural integrity of the dam. This type of cement is also beneficial in preventing thermal expansion and contraction, which can lead to cracks and leaks in the dam. Therefore, low heat cement is the most suitable option for constructing dams to ensure their long-term durability and stability.Rate this question:
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- 10.
Sulphate resisting cement contains a small proportion of
- A.
Silicate
- B.
Tricalcium aluminates
- C.
Dicalcium silicates
- D.
Alumina
Correct Answer
B. Tricalcium aluminatesExplanation
Sulphate resisting cement contains a small proportion of tricalcium aluminates. Tricalcium aluminates are compounds that contribute to the strength and durability of the cement. They react with water to form calcium silicate hydrates, which are responsible for the hardening of the cement. In sulphate resisting cement, the presence of tricalcium aluminates helps to protect the cement from the harmful effects of sulphate ions, which can cause deterioration and cracking. By incorporating tricalcium aluminates, sulphate resisting cement is able to withstand exposure to sulphate-rich environments, making it suitable for construction in areas where sulphates are present in the soil or water.Rate this question:
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- 11.
In soundness test, after immersing whole assembly in water for 24 hours, distance between the indicator points is measured
- A.
Assembly then returned to water
- B.
Brought to boiling in 25 to 30 minutes & boiled for 1 hour
- C.
After cooling, distance between indicator points is again measured
- D.
All of these
Correct Answer
D. All of theseExplanation
In a soundness test, the distance between the indicator points is measured after immersing the assembly in water for 24 hours. This is done to check if there are any leaks or cracks in the assembly that would cause water to seep in. After measuring the distance, the assembly is returned to water and brought to a boil for 1 hour. Boiling the assembly helps to simulate extreme conditions and further tests its durability. After cooling down, the distance between the indicator points is measured again to see if there have been any changes or damages to the assembly. Therefore, all of these steps are part of the soundness test.Rate this question:
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- 12.
In soundness test, the difference between distance between indicator points before and after cooling should not be more than
- A.
5 mm
- B.
10 mm
- C.
15 mm
- D.
20 mm
Correct Answer
B. 10 mmExplanation
In a soundness test, the difference between the distance between indicator points before and after cooling should not be more than 10 mm. This means that the structure being tested should not experience significant deformation or displacement during the cooling process. If the difference exceeds 10 mm, it indicates that there may be weaknesses or flaws in the structure that could compromise its stability and integrity. Therefore, a difference of 10 mm or less ensures that the structure remains sound and can withstand the cooling process without any significant changes.Rate this question:
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- 13.
In determining tensile strength of cement, test briquettes are made of
- A.
Cement
- B.
Sand
- C.
Mortar
- D.
Concrete
Correct Answer
C. MortarExplanation
Test briquettes are made of mortar to determine the tensile strength of cement. Mortar is a mixture of cement, sand, and water, and it is commonly used as a bonding material in construction. By testing the tensile strength of mortar, which includes cement as one of its components, it provides an accurate measure of the cement's ability to withstand tension or pulling forces. Testing the tensile strength of cement directly would not be practical or feasible, so using mortar as a representative sample allows for a more practical and reliable assessment.Rate this question:
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- 14.
In determining tensile strength of cement, the ratio of cement and sand in mortar meant for test briquette is
- A.
1:1
- B.
1:2
- C.
1:3
- D.
1:6
Correct Answer
C. 1:3Explanation
The correct answer is 1:3 because in order to determine the tensile strength of cement, a test briquette is made using a mixture of cement and sand. The ratio of cement to sand in this mixture is 1:3. This ratio is important as it helps to create a strong and durable test briquette that accurately represents the strength of the cement being tested.Rate this question:
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- 15.
In determining tensile strength of cement, the water content(by weight) used in mortar meant for test briquette is
- A.
8% of cement and sand combined
- B.
12% of cement and sand combined
- C.
16% of cement and sand combined
- D.
What required for standard consistency
Correct Answer
A. 8% of cement and sand combinedExplanation
The correct answer is 8% of cement and sand combined. In determining the tensile strength of cement, the water content used in the mortar meant for the test briquette is 8% of the combined weight of cement and sand. This specific water content is necessary to achieve the standard consistency required for accurate testing of the cement's tensile strength.Rate this question:
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- 16.
Tensile strength of concrete is measured by
- A.
Direct tension test in the universal testing machine
- B.
Applying compressive load along the diameter of the cylinder
- C.
Applying third point loading on a prism
- D.
Applying tensile load along the diameter of the cylinder
Correct Answer
B. Applying compressive load along the diameter of the cylinderExplanation
The correct answer is applying compressive load along the diameter of the cylinder. Tensile strength refers to the ability of a material to resist breaking or splitting under tension. However, concrete is a brittle material and has low tensile strength. Therefore, instead of directly measuring the tensile strength, it is measured indirectly by applying compressive load along the diameter of the cylinder. This is because when compressive load is applied, it causes tensile stresses to develop perpendicular to the applied load, which can be used to determine the tensile strength of the concrete.Rate this question:
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- 17.
The total surface area of one gram cement per square centimeters is known as
- A.
Fineness
- B.
Specific surface
- C.
Specific volume
- D.
None of these
Correct Answer
B. Specific surfaceExplanation
The correct answer is "specific surface". Specific surface refers to the total surface area of one gram of cement per square centimeter. It is a measure of the fineness or particle size distribution of the cement. A higher specific surface indicates a finer cement, which can affect its properties and performance in various applications. Specific volume, on the other hand, refers to the volume occupied by one gram of cement, and fineness is a term used to describe the particle size of the cement. Therefore, the correct term for the given definition is specific surface.Rate this question:
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- 18.
Turbid meter test is used for measuring
- A.
Setting time
- B.
Soundness
- C.
Tensile strength
- D.
Specific surface
Correct Answer
D. Specific surfaceExplanation
The turbid meter test is used for measuring the specific surface of a material. This test is based on the principle that the amount of light scattered by a suspension is directly proportional to the surface area of the particles present in the suspension. By measuring the turbidity of the suspension, the specific surface area can be determined. Therefore, the correct answer is specific surface.Rate this question:
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- 19.
In turbid meter test, cement is kept in suspension in
- A.
Petrol
- B.
Diesel
- C.
White kerosene
- D.
Any of these
Correct Answer
C. White keroseneExplanation
In the turbid meter test, cement is kept in suspension in white kerosene. This is because white kerosene has properties that allow it to effectively suspend the cement particles, ensuring that they remain evenly distributed in the liquid. Petrol and diesel may not have the same suspension properties as white kerosene, making them less suitable for this test. Therefore, white kerosene is the preferred choice for keeping cement in suspension during the turbid meter test.Rate this question:
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- 20.
In the turbid meter test to determine fineness of cement
- A.
A laser beam passes through the solution
- B.
An X ray passes through the solution
- C.
A ray of light passes through the solution
- D.
None of these
Correct Answer
C. A ray of light passes through the solutionExplanation
The correct answer is that a ray of light passes through the solution. In the turbid meter test, a ray of light is used to determine the fineness of cement. The light passes through the solution and the amount of light that is scattered or absorbed by the particles in the solution is measured. This measurement helps to determine the size and distribution of the particles in the cement, which is an important factor in assessing its quality.Rate this question:
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Sekolah Global Mandiri - Wilayah Negara Kesatuan Republik Indonesia
Sekolah Global Mandiri - Wilayah Negara Kesatuan Republik Indonesia
Seleksi Penerimaan Mahasiswa Baru Poltekkes Hermina Tahun 2020
Seleksi Penerimaan Mahasiswa Baru Poltekkes Hermina Tahun 2020
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