1.
The minimum penetration of the preservative with the surface timber piles shall be?
Correct Answer
B. 200mm
Explanation
The minimum penetration of the preservative with the surface timber piles should be 200mm. This depth ensures that the preservative effectively protects the timber from decay and insect damage. A deeper penetration would provide even better protection, but 200mm is the minimum requirement to ensure the longevity of the timber piles.
2.
Scales for weighing aggregates and cement shall be accurate within % throughout the range of use., Scales shall be inspected and sealed as often as the Engineer may deem necessary to assure their continued accuracy.
Correct Answer
C. 0.5%
Explanation
The correct answer is 0.5%. This means that the scales used for weighing aggregates and cement must be accurate within 0.5% throughout the range of use. It is important for the scales to be inspected and sealed regularly to ensure their continued accuracy, as deemed necessary by the Engineer. This level of accuracy is necessary to ensure that the right amount of aggregates and cement are used in construction projects, as even small deviations can affect the quality and strength of the final product.
3.
When cement is placed in contact with the aggregate , batches may rejected unless mixed with __ hours of such contact.
Correct Answer
A. 1.5
Explanation
When cement comes in contact with aggregate, it starts to hydrate and harden. If this contact lasts for too long, it can lead to a loss of workability and strength in the concrete mix. Therefore, in order to prevent this, the cement and aggregate should be mixed within 1.5 hours of coming into contact with each other. This ensures that the concrete mix remains of good quality and can be used for construction purposes.
4.
When mixed at the site or in a central mixing plant, the mixing time shall not be less than __ nor more than __ unless mixer performance test prove adequate mixing of concrete in a short period of time.
Correct Answer
B. 50 seconds nor more than 90 seconds
Explanation
When mixing concrete at the site or in a central mixing plant, the mixing time should ideally be between 50 seconds and 90 seconds. This range ensures that the concrete is adequately mixed. However, if mixer performance tests demonstrate that the concrete can be properly mixed in a shorter period of time, then the mixing time can be reduced. It is important to find the right balance between mixing the concrete thoroughly and minimizing the time required for the mixing process.
5.
The flow of water shall be uniform and all water should be in drum by the end of the first__ seconds of the mixing period.
Correct Answer
C. 15
Explanation
The correct answer is 15 because it is stated that the flow of water should be uniform and all water should be in the drum by the end of the first 15 seconds of the mixing period. This means that within the first 15 seconds, all the water should have been added to the drum and there should be no more water flowing after this time.
6.
Concrete not place within __minutes from the time the ingredients were charged into the mixing drum shall be used.
Correct Answer
D. 90
Explanation
The correct answer is 90. This means that if the concrete is not placed within 90 minutes from the time the ingredients were charged into the mixing drum, it should not be used. This time limit ensures that the concrete is still fresh and workable, as concrete that sits for too long can lose its desired properties and become less effective for construction purposes.
7.
The contractor shall submit in writing a job mix formula for the mixture supported by laboratory test data along with samples of resources of components and viscous temperature relationships to the engineer for testing and approval at least.
Correct Answer
B. 3 weeks
Explanation
The contractor is required to submit a job mix formula for the mixture, along with laboratory test data and samples of resources, to the engineer for testing and approval. This process takes a certain amount of time, and the contractor must submit these documents at least 3 weeks before the testing and approval is needed. This allows the engineer enough time to review and assess the job mix formula and make a decision.
8.
The concrete sample should be stored in a moist condition temperature within the range of __until the time of tests
Correct Answer
A. 18* c -24*c
Explanation
The concrete sample should be stored in a moist condition temperature within the range of 18°C - 24°C until the time of tests. This temperature range is ideal for maintaining the moisture content of the concrete sample, which is important for its proper curing and testing. Lower temperatures may slow down the curing process, while higher temperatures may cause excessive drying and shrinkage of the sample. Therefore, maintaining a temperature between 18°C - 24°C ensures optimal conditions for the concrete sample's storage.
9.
This is used in soil stabilized road surface due to its high __ property, that is, it absorb the retain water
Correct Answer
B. Magnessium chloride
Explanation
Magnesium chloride is used in soil stabilized road surfaces due to its high absorbent property, meaning it can absorb and retain water. This property helps to prevent the road surface from becoming too dry or too wet, which can lead to cracking, potholes, and other damage. Magnesium chloride helps to maintain the stability and integrity of the road, making it a suitable choice for soil stabilization.
10.
Which of the following alloying elements is most effective in increasing the hardness of steel through the formation of carbides?
Correct Answer
A. Chromium
Explanation
Chromium is highly effective in increasing the hardness of steel through the formation of hard chromium carbides (CrC). These carbides significantly enhance wear resistance and hardness, making chromium a key element in tool steels and stainless steels. While other elements like nickel and manganese contribute to toughness and strength, they do not form carbides as effectively as chromium. Silicon primarily acts as a deoxidizer and does not contribute significantly to hardness through carbide formation.
11.
Which of the following microstructural features in metals is most critical for enhancing resistance to fatigue failure?
Correct Answer
C. Fine grain size
Explanation
Fine grain size is crucial for improving a metal's resistance to fatigue failure. Smaller grains provide more grain boundaries, which act as barriers to crack initiation and propagation, a primary cause of fatigue failure. This enhances the material's overall durability under cyclic loading conditions. Large grain size and coarse pearlite can reduce fatigue strength, while high dislocation density can increase strength but may also increase susceptibility to fatigue under certain conditions.
12.
Cast in place concrete shall not be post tentioned until at least ___ and until the compressive strength has reached the strength specified
Correct Answer
B. 10
Explanation
The correct answer is 10. Cast-in-place concrete should not be post-tensioned until at least 10 days have passed and until the compressive strength of the concrete has reached the strength specified. This waiting period allows the concrete to properly cure and gain sufficient strength to withstand the tensioning forces applied during post-tensioning. It is important to ensure that the concrete has reached the specified strength to prevent any potential structural issues or failures.
13.
The penetration test is an indication of the __of asphalt
Correct Answer
A. Consistency
Explanation
The penetration test is a method used to measure the consistency of asphalt. It involves measuring the depth to which a standard needle penetrates the asphalt sample under specific conditions. The consistency of asphalt refers to its ability to flow or deform under load. A higher penetration value indicates a softer consistency, while a lower penetration value indicates a harder consistency. Therefore, the correct answer in this case is consistency.
14.
The __ is the most commonly used method in the design and evaluation of bituminous concrete mixes
Correct Answer
B. Marshall stability
Explanation
Marshall stability is the most commonly used method in the design and evaluation of bituminous concrete mixes. This method measures the resistance of the mix to deformation and cracking under load. It involves compacting a cylindrical specimen of the mix and subjecting it to a load until failure occurs. The load at which failure occurs, known as Marshall stability, is used to determine the quality and performance of the mix. This method is widely accepted and used in the industry due to its reliability and correlation with field performance.
15.
Vibration shall operate a frequency of 8300 to 9600 impulses per minute under load at a maximum spacing of __cm
Correct Answer
D. 60
Explanation
The correct answer is 60 because the question states that the vibration shall operate at a frequency of 8300 to 9600 impulses per minute under load. The maximum spacing of the vibration is not specified in the question, so we can assume that the maximum spacing is not restricted. Therefore, the maximum spacing can be any value, but it must be less than or equal to 60 cm in order to fulfill the given frequency range.
16.
The sp, gravity of sodium sulfate used in soundness test for aggregate should be in range of
Correct Answer
C. 1
1.151-1.174
Explanation
The correct answer is 1.151-1.174. In the soundness test for aggregate, sodium sulfate is used to determine the resistance of the aggregate to disintegration. The specific gravity of the sodium sulfate solution used in this test should fall within the range of 1.151-1.174. This specific gravity range ensures that the concentration of sodium sulfate is appropriate for the test and will provide accurate results in determining the soundness of the aggregate.
17.
Aggregate accounts for 92-95% of the weight of the bituminous mixture asphalt accounts 5-8% of the weight of the mix. the exact % to be used is determined by the__
Correct Answer
B. Trial mix
Explanation
The correct answer is trial mix. The exact percentage of asphalt to be used in the bituminous mixture is determined through a trial mix. This involves conducting tests and experiments to find the optimal ratio of asphalt to aggregate that will result in the desired properties and performance of the asphalt mix. The trial mix helps in determining the appropriate proportions of materials to achieve the desired strength, durability, and workability of the asphalt mixture.
18.
The sp. gravity of magnesium sulfate used in the soundness test
Correct Answer
C. 1.295-1.308
Explanation
The correct answer is 1.295-1.308. This range represents the specific gravity of magnesium sulfate used in the soundness test. The specific gravity is a measure of the density of a substance compared to the density of water. In the soundness test, magnesium sulfate is used to determine the durability of cement by subjecting it to cycles of wetting and drying. The specific gravity of the magnesium sulfate solution is important in ensuring accurate and consistent test results.
19.
In checking the temp of the mix , the thermometer should be inserted into the mix at least__inches
Correct Answer
A. 2
Explanation
The correct answer is 2 because inserting the thermometer at least 2 inches into the mix ensures that an accurate temperature reading is obtained. This depth allows the thermometer to be immersed in the mix enough to provide an accurate representation of the overall temperature. If the thermometer is not inserted deep enough, it may not accurately measure the temperature of the entire mix.
20.
__ is applied on existing bit, or cement concrete surface with bitum matls
Correct Answer
A. Bituminous tack coat
Explanation
A bituminous tack coat is applied on an existing bit or cement concrete surface with bituminous materials. This coat helps to create a bond between the existing surface and the new bituminous layer that will be applied on top. It ensures better adhesion and prevents the new layer from delaminating or separating from the existing surface. The tack coat acts as a glue, providing a strong and durable connection between the two layers.
21.
Which of the following materials is most suitable for high-temperature applications due to its ability to maintain structural integrity at temperatures exceeding 1200°C?
Correct Answer
C. Nickel-based Superalloys
Explanation
Nickel-based superalloys are specifically designed to withstand extreme temperatures, often exceeding 1200°C, without losing strength or structural integrity. They are commonly used in high-temperature environments such as jet engines and gas turbines. Aluminum and titanium, while strong and lightweight, cannot maintain their structural properties at such high temperatures. Stainless steel has higher temperature resistance than aluminum and titanium but still falls short compared to nickel-based superalloys.
22.
Proper compaction of the fill matls is very important, as it will
Correct Answer
D. All of the above
Explanation
Proper compaction of the fill materials is important because it has multiple benefits. Firstly, it increases the shear strength of the material, making it more resistant to sliding or deformation. Secondly, it decreases permeability, which means that it reduces the ability of water or other fluids to pass through the material. Finally, it minimizes compressibility, ensuring that the material remains stable and does not settle or deform under load. Therefore, all of the above benefits can be achieved by proper compaction of the fill materials.
23.
In concrete acceptance , core will be considered adequate if the average strength of the cores is = to what?
Correct Answer
C. 85% of specified strength and if no single core is less than 75% of specified strength
Explanation
The correct answer is 85% of specified strength and if no single core is less than 75% of specified strength. This means that in concrete acceptance, the average strength of the cores should be equal to or greater than 85% of the specified strength. Additionally, no single core should have a strength less than 75% of the specified strength. This ensures that the concrete cores are adequately strong and meet the required standards for acceptance.
24.
The cohesion and internal friction of soil shall be tested by
Correct Answer
D. All
Explanation
The cohesion and internal friction of soil can be tested using various methods, including the triaxial test, direct shear test, and bearing test. Each of these tests evaluates different aspects of the soil's behavior under stress. The triaxial test measures the shear strength and stress-strain relationship of the soil, while the direct shear test determines the shear strength along a single plane. The bearing test assesses the soil's ability to support a load. Therefore, all of these tests are suitable for testing the cohesion and internal friction of soil.
25.
Before the cement is to be used , sampling must be done at least __-before use
Correct Answer
A. 1 wk
Explanation
Sampling must be done at least 1 week before the cement is to be used. This is important to ensure that the cement meets the required quality standards and to allow enough time for any necessary adjustments or corrective actions to be taken if the sampled cement does not meet the desired specifications. Sampling in advance also allows for proper testing and analysis of the cement to be conducted, providing accurate and reliable results.
26.
Asphalt cement shall not be used while it is foaming nor shall be heated @ __ anytime after delivery
Correct Answer
B. 159*
27.
Moisture content of aggregate in bit mix shall not exceed __of the time it is introduce into the mixing unit
Correct Answer
D. 1%
Explanation
The moisture content of aggregate in bit mix should not exceed 1% of the time it is introduced into the mixing unit. This is important because excessive moisture can negatively affect the quality and performance of the bit mix. It can lead to poor adhesion between the aggregate and bitumen, resulting in reduced stability and durability of the pavement. Additionally, excess moisture can cause the bit mix to become unstable and difficult to compact, leading to uneven surfaces and potential pavement failures. Therefore, it is crucial to carefully control and monitor the moisture content of the aggregate during the mixing process to ensure optimal performance of the bit mix.
28.
Batching tolerance for sand and aggregate is___
Correct Answer
C. 3
Explanation
The correct answer is 3 because batching tolerance refers to the acceptable range of variation in the quantity of sand and aggregate used in a batch of concrete. A tolerance of 3% means that the actual quantity of sand and aggregate used can deviate by up to 3% from the specified quantity without affecting the quality of the concrete. This allows for minor variations in the materials and ensures that the concrete mix remains within acceptable limits.
29.
Between stage of curing , concrete shall not be exposed for more than ___ hours
Correct Answer
A. 24
Explanation
During the stage of curing, it is important to protect the concrete from drying out too quickly. If concrete is exposed for more than 24 hours, it can lead to a loss of moisture and result in a weaker and less durable final product. This is because the curing process allows the concrete to gain strength and develop its desired properties. Therefore, it is crucial to ensure that the concrete is not exposed for more than 24 hours to maintain its quality and integrity.
30.
As a matls engineer , what will you do with the major honeycombed area that is considered as defective work
Correct Answer
B. Removed and replaced at the expensed of the contractor
Explanation
The correct answer suggests that as a materials engineer, the major honeycombed area that is considered defective work should be removed and replaced at the expense of the contractor. This means that the contractor is responsible for fixing the issue and covering the costs associated with the replacement.
31.
If the strentgh of control specimen does not meet the req. and not feasible to obtain cores due to structural considerations , as a matls engr what will be your decision?
Correct Answer
C. Payment will be made at an adjusted price
Explanation
If the strength of the control specimen does not meet the requirements and it is not possible to obtain cores due to structural considerations, the decision as a materials engineer would be to make payment at an adjusted price. This means that the payment for the project will be modified based on the lower strength of the control specimen. This adjustment accounts for the deviation from the specified requirements and ensures fair compensation for the work done.
32.
After concrete has been placed , it is advisable to maintain fully welted and in position for how many hours
Correct Answer
C. 72
Explanation
After concrete has been placed, it is advisable to maintain it fully wetted and in position for 72 hours. This is because during this time, the concrete undergoes the process of hydration, where it reacts with water to form a strong and durable solid structure. Maintaining the concrete wet helps to prevent it from drying out too quickly, which can lead to cracking and reduced strength. By keeping it wet for 72 hours, the concrete can properly cure and achieve its maximum strength and durability.
33.
Rock shall be excavated to a depth ___below sub grade within the limit of the roadbed
Correct Answer
B. 150
Explanation
The correct answer is 150. This means that when excavating rock for the roadbed, it should be dug to a depth of 150mm below the subgrade level. This is important to ensure proper stability and support for the road. Excavating to this depth will allow for proper compaction and the placement of suitable materials for the road construction.
34.
Minimum penetration of piles shall be__
Correct Answer
A. 3m
Explanation
The minimum penetration of piles shall be 3m. This means that the piles must be driven into the ground to a depth of at least 3 meters. This requirement is important to ensure the stability and load-bearing capacity of the piles, as a sufficient depth of penetration helps to anchor the piles securely and distribute the load effectively. A deeper penetration also helps to avoid any potential issues such as settlement or lateral movement of the piles. Therefore, it is essential to adhere to this minimum penetration requirement for the successful construction of the piles.
35.
Piles shall not be driven within 7 meters of concrete less than__days
Correct Answer
A. 7
Explanation
Piles should not be driven within 7 meters of concrete less than 7 days old. This is because freshly poured concrete needs time to cure and gain strength. Driving piles too close to new concrete can cause damage and compromise the stability of the structure. Therefore, it is important to wait at least 7 days before driving piles near recently poured concrete.
36.
Minimum thickness of bedding materials beneath the pipe is___
Correct Answer
A. 100mm
Explanation
The minimum thickness of bedding materials beneath the pipe is 100mm. This means that when installing the pipe, there needs to be a layer of bedding material that is at least 100mm thick underneath it. This thickness is necessary to provide proper support and stability to the pipe, ensuring that it is securely positioned and protected from any external pressures or movements. A thinner bedding material may not offer sufficient support, while a thicker one may be unnecessary and wasteful. Therefore, the correct answer is 100mm.
37.
Unconfined compressive strength test is usually performed on
Correct Answer
C. Clayey
Explanation
The Unconfined Compressive Strength (UCS) test is typically performed on cohesive soils, particularly clayey soils. This test measures the soil's strength under unconfined conditions, meaning no lateral support is provided during the test. Clay soils, which have high cohesion and plasticity, are well-suited for this type of testing, whereas sandy and silty soils, which are less cohesive, are not typically tested using UCS.
38.
Tolerance of gabion dimension is_-
Correct Answer
C. +- 3%
Explanation
The correct answer is +- 3% because tolerance refers to the allowable deviation from the specified dimension. In this case, the tolerance for gabion dimension is +- 3%, meaning that the actual dimension of the gabion can vary by up to 3% from the specified dimension. This allows for a certain level of flexibility in the manufacturing process while still ensuring that the gabion meets the required standards and specifications.
39.
Minimum size of galvanized wire mesh is __
Correct Answer
B. 2.2
Explanation
The minimum size of galvanized wire mesh is 2.2mm. This means that the smallest diameter of the wire used in the mesh should be 2.2mm. Galvanized wire mesh is commonly used for various applications such as fencing, construction, and agriculture. The galvanization process involves coating the wire with a protective layer of zinc, which enhances its durability and resistance to corrosion. Choosing the appropriate size of the wire mesh is important to ensure its strength and effectiveness for the intended purpose.
40.
Minimum density of gabions
Correct Answer
C. 1400kg/cu m
Explanation
Gabions are wire mesh containers filled with stones or other materials used for erosion control and retaining walls. The minimum density of gabions refers to the minimum weight per unit volume that the gabions should have to ensure stability and effectiveness. In this case, the correct answer is 1400kg/cu m, which means that the gabions should have a density of 1400 kilograms per cubic meter to meet the minimum requirements. This density ensures that the gabions are heavy enough to withstand external forces and provide the necessary support and protection.
41.
Paint contains __-% pigment and vehicle___
Correct Answer
B. 21,79
Explanation
The correct answer is 21,79. This means that paint contains 21% pigment and 79% vehicle. Pigment is the component that provides color and opacity to the paint, while the vehicle is the liquid that holds the pigment together and allows it to be applied. This ratio ensures that the paint has enough pigment to achieve the desired color and coverage while still being fluid enough to be easily applied.
42.
Soundness loss of field gabions is__
Correct Answer
A. 9% after 5 cycles
Explanation
The soundness loss of field gabions is 9% after 5 cycles. This means that after undergoing 5 cycles of testing or use, the field gabions experience a loss in soundness of 9%. This could refer to a decrease in their structural integrity, stability, or overall effectiveness. It suggests that the gabions may become less reliable or durable over time, potentially impacting their ability to serve their intended purpose.
43.
The depth of the weakened joints must not be less than __ and width of__
Correct Answer
B. 50mm & 6mm
Explanation
The depth of the weakened joints must not be less than 50mm and the width must be 6mm. This is likely because a depth of 50mm provides enough space for the weakened joint to be effective in distributing stress and preventing failure. The width of 6mm may be sufficient for the specific application or material being used.
44.
The lenght of shelby tube of an undisturbed sample__
Correct Answer
D. 18" long
Explanation
The correct answer is 18" long. This suggests that the length of the Shelby tube used for obtaining an undisturbed sample is 18 inches long.
45.
What is the temp of the concrete sample?
Correct Answer
B. 18-24
Explanation
The correct answer is 18-24. This range represents the temperature of the concrete sample. The temperature of the concrete is an important factor to consider during construction and curing processes. This range ensures that the concrete is within the optimal temperature range for proper curing and strength development. Concrete that is too hot or too cold can result in poor quality and compromised structural integrity. Therefore, maintaining a temperature range of 18-24 degrees Celsius is crucial for achieving the desired outcomes in concrete construction.
46.
__ is the rate of loading for concrete cylinder sample subject to a compression test
Correct Answer
C. 20-50 Psi
Explanation
The rate of loading for concrete cylinder sample subject to a compression test is typically measured in pounds per square inch (Psi). The correct answer is 20-50 Psi, which means that the concrete cylinder sample should be loaded at a rate between 20 and 50 pounds per square inch. This range ensures that the sample is subjected to an appropriate level of pressure during the test, allowing for accurate measurement of its compressive strength.
47.
What is the plasticity index of mineral filler?
Correct Answer
C. Not greater than 4
Explanation
The plasticity index of mineral filler should not be greater than 4. This means that the mineral filler should have a low plasticity, indicating that it does not easily deform or change shape under stress. A plasticity index greater than 4 would indicate a higher level of plasticity, which may not be desirable for certain applications where stability and stiffness are important factors. Therefore, it is important for the plasticity index of mineral filler to be limited to a value that is not greater than 4.
48.
In the process of heat treatment, which phase transformation in steel is responsible for the formation of martensite?
Correct Answer
B. Austenite to Martensite
Explanation
Martensite forms during the heat treatment of steel when austenite (a high-temperature phase of steel) is rapidly cooled, typically through quenching. This rapid cooling prevents the carbon atoms in the austenite from diffusing out, resulting in a distorted crystal structure known as martensite. Martensite is a very hard and brittle phase, crucial in increasing the strength and hardness of steel. Other phase transformations do not produce martensite.
49.
____ is the slump of workable concrete if vibrated
Correct Answer
C. 10-40mm
Explanation
The slump of workable concrete refers to the amount of vertical settlement or sag that occurs when the concrete is subjected to vibration. A slump of 10-40mm indicates that the concrete has a moderate level of workability, allowing it to be easily placed and compacted. This range ensures that the concrete is not too stiff or too fluid, striking a balance between ease of handling and achieving the desired strength and durability.
50.
How many hours do aggregate stockpile or binned for draining before being batch?
Correct Answer
C. 12
Explanation
The correct answer is 12. This suggests that aggregate stockpile or binned materials need to be drained for 12 hours before being batched. This process allows any excess moisture or water to be removed from the materials, ensuring that the batch is of high quality and meets the required specifications.