1.
Which plasticity index is most suitable for aggregate base course?
Correct Answer
A. 5
Explanation
A plasticity index of 5 is most suitable for aggregate base course. This is because a lower plasticity index indicates that the material has less clay content, which is desirable for the aggregate base course. Clay can cause the material to become too cohesive and susceptible to swelling and shrinkage, leading to potential damage and instability. Therefore, a plasticity index of 5 ensures that the material has a minimal clay content, making it suitable for the aggregate base course.
2.
The specified flexural strength for paving concrete is
Correct Answer
C. 525
Explanation
The specified flexural strength for paving concrete is 525. This means that the concrete used for paving needs to have a minimum flexural strength of 525 pounds per square inch (psi) in order to withstand the stresses and loads that it will be subjected to. Flexural strength is a measure of a material's ability to resist deformation under bending, and in the case of paving concrete, it is crucial to ensure that it is strong enough to withstand the weight of vehicles and other external forces. Therefore, a flexural strength of 525 psi is the correct specification for paving concrete.
3.
The sample of 12.5mm diameter steel bar to be submitted for test should be at least
Correct Answer
C. 100cm
Explanation
The sample of 12.5mm diameter steel bar should be at least 100cm in length. This is because a longer sample allows for more accurate and representative testing. With a longer sample, there is a greater chance of capturing any variations or defects that may be present in the steel bar. Additionally, a longer sample provides more material for testing, which can help ensure reliable and consistent results. Therefore, a 100cm length is the most appropriate choice for submitting the sample for testing.
4.
_____ is the method used in determining the strenght of concrete pipe.
Correct Answer
B. Three-edge bearing test
Explanation
The three-edge bearing test is used to determine the strength of a concrete pipe. This test involves applying a load to the top of the pipe while it is supported on three edges. The test measures the ability of the pipe to withstand external pressure and determines its load-carrying capacity. This method is commonly used in the construction industry to ensure the durability and reliability of concrete pipes.
5.
Prestressed concrete requires the used of Class __ concrete.
Correct Answer
D. D
Explanation
Prestressed concrete requires the use of Class D concrete because it has a high compressive strength and low water-cement ratio, which makes it ideal for withstanding the tension forces created by the prestressing process. Class D concrete also has good durability and resistance to shrinkage, making it suitable for long-term structural applications.
6.
If an asphalt pavement will be constructed over an old existing concrete pavement ___ should be applied to the concrete pavement.
Correct Answer
B. Tack coat
Explanation
When constructing an asphalt pavement over an old existing concrete pavement, a tack coat should be applied to the concrete pavement. A tack coat is a thin layer of asphalt emulsion that is sprayed onto the existing pavement surface. It helps to create a bond between the old and new pavement layers, ensuring better adhesion and preventing the new asphalt layer from separating or delaminating from the concrete pavement. This improves the overall durability and performance of the asphalt pavement.
7.
For bituminous concrete mixes, the asphalt material may either be asphalt cement or asphalt emulsion
Correct Answer
A. True
Explanation
Bituminous concrete mixes can be made using either asphalt cement or asphalt emulsion as the asphalt material. Asphalt cement is a semi-solid form of petroleum that is commonly used in road construction. Asphalt emulsion, on the other hand, is a mixture of asphalt cement, water, and an emulsifying agent. It is a more environmentally friendly option as it requires less energy to produce and can be applied at lower temperatures. Therefore, the statement that the asphalt material for bituminous concrete mixes can be either asphalt cement or asphalt emulsion is true.
8.
Coarse Aggregate for Bituminous Macadam Pavement should be
Correct Answer
A. Crushed gravel or stone
Explanation
The correct answer is crushed gravel or stone because bituminous macadam pavement requires a strong and durable coarse aggregate that can withstand heavy traffic loads. Crushed gravel or stone provides the necessary strength and stability to the pavement, making it suitable for use in this type of road construction. Natural gravel may not have the same level of strength and durability as crushed gravel or stone, making it less suitable for bituminous macadam pavement. Therefore, the correct choice is crushed gravel or stone.
9.
Test for coarse aggregate includes
Correct Answer
B. Abrasion/absorption
Explanation
The test for coarse aggregate includes abrasion and absorption. Abrasion refers to the resistance of the aggregate to wear and tear, while absorption measures the ability of the aggregate to absorb water. These tests are important in determining the durability and strength of the coarse aggregate, as well as its suitability for use in construction projects. By conducting these tests, engineers can ensure that the aggregate meets the required standards and will perform well in the intended application.
10.
Test for fine aggregate for concrete includes
Correct Answer
C. Gradation/mortar strength
Explanation
The test for fine aggregate for concrete includes evaluating the gradation of the aggregate particles and determining the mortar strength. Gradation refers to the distribution of particle sizes in the aggregate, which is important for achieving a dense and workable concrete mix. The mortar strength test assesses the bonding ability of the aggregate with the cement paste, which is crucial for the overall strength and durability of the concrete. Therefore, both gradation and mortar strength are essential factors to consider when testing fine aggregate for concrete.
11.
Unless otherwise specified in the special provision, the type of portland cement used in paving concrete shall be
Correct Answer
A. Type I
Explanation
The correct answer is type I because unless otherwise specified, type I portland cement is typically used in paving concrete.
12.
During construction of road project, if all the materials to be used are tested for quality, inspection is no longer required?
Correct Answer
B. False
Explanation
Inspection is still required even if all the materials used in the construction of a road project are tested for quality. Testing the materials ensures that they meet the required standards, but inspection is necessary to ensure that the materials are being used correctly and that the construction process is being carried out properly. Inspection helps to identify any potential issues or errors that may arise during the construction process and allows for timely corrections to be made. Therefore, the statement that inspection is no longer required is false.
13.
The degree of compaction of an embankment in our present Specifications is based on
Correct Answer
C. AASHTO designation T-180
Explanation
The AASHTO designation T-180 is used as the basis for determining the degree of compaction of an embankment in our present Specifications. This designation refers to a test method developed by the American Association of State Highway and Transportation Officials (AASHTO) to measure the moisture-density relationship of soils. By using this method, engineers can determine the optimum moisture content and maximum dry density of the soil, which are crucial factors in achieving the desired level of compaction for the embankment.
14.
Under excavation for structure, Item 106, the backfilling operation shall be done in ___ cm loose layer and compacted to at least __ percent.
Correct Answer
C. 20,95
Explanation
During the excavation for a structure, the backfilling operation requires a loose layer of 20 cm. This means that the backfill material should be placed in layers that are 20 cm thick. Additionally, the backfill material needs to be compacted to at least 95 percent. This ensures that the backfill is properly settled and provides stability and support to the structure.
15.
Soil are natural aggregates of minerals connected by strong and permanent cohesive forces?
Correct Answer
B. False
Explanation
The statement is false because soil is not composed solely of minerals. It also contains organic matter, water, and air. Additionally, the cohesive forces in soil are not always strong and permanent, as they can vary depending on the composition and moisture content of the soil.
16.
The boundary between sand and gravel is
Correct Answer
C. 2.00mm (#10)
Explanation
The correct answer is 2.00mm (#10). The boundary between sand and gravel is determined by the size of the particles. Sand particles are larger than 0.075mm (#200) but smaller than 2.00mm (#10). Gravel particles, on the other hand, are larger than 2.00mm (#10). Therefore, the 2.00mm (#10) size represents the boundary between sand and gravel.
17.
____ is a soil which exhibits the properties of a clay but contains an appreciable amount of sand.
Correct Answer
A. Sandy clay
Explanation
Sandy clay is a type of soil that has characteristics of both clay and sand. It has a higher percentage of sand particles compared to clay, but still retains some clay properties. This means that sandy clay will have better drainage and less water-holding capacity compared to pure clay soil. It is often found in areas where there is a mixture of clay and sand deposits, resulting in a soil type that is intermediate between the two.
18.
Plasticity test is done on soils passing
Correct Answer
A. 0.425mm (#40)
Explanation
The plasticity test is conducted on soils that pass through a sieve with a size of 0.425mm (#40). This test helps to determine the plasticity characteristics of the soil, such as its ability to undergo deformation without breaking. By conducting the test on particles that are smaller than 0.425mm, it ensures that the soil sample used for the test is representative of the fine-grained portion of the soil, which is where the plasticity properties are typically observed.
19.
____ is the process whereby soil particles are contained more closely together through a reduction in the air voids, generally by mechanical means.
Correct Answer
A. Soil compaction
Explanation
Soil compaction is the process of reducing the air voids between soil particles through mechanical means. This can be achieved by applying pressure or using equipment to compress the soil, resulting in increased density. Compacted soil has improved stability, load-bearing capacity, and reduced permeability. It is commonly used in construction projects to ensure a solid foundation for buildings, roads, and other structures.
20.
Soils containing more than 35% passing 0.075mm (#200) sieve are classified under
Correct Answer
A. Silty-clay materials
Explanation
Soils containing more than 35% passing 0.075mm (#200) sieve are classified as silty-clay materials. This classification is based on the particle size distribution of the soil. Silty-clay materials have a high percentage of fine particles, which are smaller than 0.075mm in size. This classification is important in understanding the properties and behavior of the soil, as silty-clay materials have specific characteristics and can have different engineering implications compared to other types of soils.
21.
____ is provided for the purpose of counteracting moisture movement within the structure either by seepage or capillary action.
Correct Answer
D. Subsoil drainage
Explanation
Subsoil drainage is provided for the purpose of counteracting moisture movement within the structure either by seepage or capillary action. By installing subsoil drainage systems, excess water is directed away from the structure, preventing it from seeping into the foundation or causing damage. This helps to control the moisture levels and prevent any potential issues caused by moisture movement, such as dampness, mold growth, or structural damage.
22.
A subgrade soil with a CBR value of __ % will require a thicker layer of subbase and base course.
Correct Answer
D. 3
Explanation
A subgrade soil with a higher CBR (California Bearing Ratio) value indicates that it has a greater strength and ability to withstand loads. Therefore, it would require a thinner layer of subbase and base course to provide the necessary support. On the other hand, a subgrade soil with a lower CBR value would be weaker and would need a thicker layer of subbase and base course to compensate for its lower strength. Therefore, a subgrade soil with a CBR value of 30% would require a thicker layer of subbase and base course.
23.
___ is one of the methods of stabilizing inferior soils.
Correct Answer
A. Particle arrangement
Explanation
Particle arrangement is one of the methods of stabilizing inferior soils. By adjusting the arrangement of particles within the soil, such as through compaction or adding stabilizing agents, the soil's strength and stability can be improved. This can help prevent issues such as settling, erosion, or structural failure. By properly arranging the particles, the soil can better support loads and resist movement, making it more suitable for construction or other purposes.
24.
The physical and engineering properties of soils may be improved by
Correct Answer
C. Both a and b
Explanation
Both compaction and stabilization can improve the physical and engineering properties of soils. Compaction involves reducing the air voids within the soil by applying mechanical force, which increases its density and strength. Stabilization, on the other hand, involves adding materials such as cement, lime, or chemical additives to the soil to enhance its strength, durability, and resistance to water. By combining compaction and stabilization techniques, the soil can achieve optimal properties for construction and engineering purposes.
25.
Water content of soils is generally based on the
Correct Answer
C. Weight of solids
Explanation
The water content of soils is generally based on the weight of solids because it is important to determine the amount of water present in relation to the solid particles in the soil. This measurement helps in understanding the soil's ability to retain water and its overall moisture content. By calculating the weight of solids, one can accurately assess the water content and make informed decisions regarding irrigation, drainage, and soil fertility.
26.
The density to which a soil can be compacted is related to
Correct Answer
C. Both a and b
Explanation
The density to which a soil can be compacted is related to both compacted efforts and water content. Compacted efforts refer to the amount of force applied to the soil during compaction, which affects its density. Water content also plays a crucial role as it affects the soil's ability to compact and its overall density. Therefore, both factors, compacted efforts and water content, are important in determining the density to which a soil can be compacted.
27.
Disturbed samples may be used for
Correct Answer
D. Any of the preceding
Explanation
Disturbed samples may be used for any of the preceding tests mentioned, which include sieve test, liquid limit, and compaction test. This means that disturbed samples can be utilized for conducting any of these tests, depending on the specific requirements of the study or analysis being carried out.
28.
A soil with a Group Index of 5 is stronger than another with a Group Index of 10
Correct Answer
A. True
Explanation
A Group Index is a measure of the strength and quality of a soil. A lower Group Index indicates a stronger soil, while a higher Group Index indicates a weaker soil. In this case, the soil with a Group Index of 5 is lower than the soil with a Group Index of 10, therefore it is stronger.
29.
___ determines the relative amount of water in the voids.
Correct Answer
C. Degree of saturation
Explanation
Degree of saturation determines the relative amount of water in the voids. It is a measure of how much of the pore space is filled with water compared to the total pore space. A higher degree of saturation indicates a higher water content in the voids, while a lower degree of saturation indicates a lower water content. Therefore, degree of saturation is the correct answer as it directly relates to the relative amount of water in the voids.
30.
____ is an asphalt formed by natural process of evaporation.
Correct Answer
A. Rock aspHalt
Explanation
Rock asphalt is formed through a natural process of evaporation. This occurs when petroleum or bitumen seeps out of the ground and is exposed to the air, causing the lighter components to evaporate and leaving behind a solid, asphalt-like material. Rock asphalt is commonly found in areas where petroleum deposits are present, such as oil sands or oil shale formations. It is often used as a paving material due to its natural occurrence and durability.
31.
Uncrushed aggregates are preferable than crushed aggregates for bituminous mixtures?
Correct Answer
C. It depends on the type of bituminous material
Explanation
The preference for uncrushed or crushed aggregates in bituminous mixtures depends on the type of bituminous material being used. Different types of bituminous materials may have different requirements for aggregate characteristics. Therefore, it is important to consider the specific type of bituminous material when deciding whether to use uncrushed or crushed aggregates in the mixture.
32.
The apparatus used in determining the consistency of liquid asphalt is the
Correct Answer
B. Viscometer
Explanation
A viscometer is an apparatus used to measure the viscosity or consistency of a liquid, such as liquid asphalt. It determines how easily the liquid flows, which is important in various industries, including paving and construction. By measuring the time it takes for a liquid to flow through a narrow tube or capillary, the viscometer provides a quantitative measure of the liquid's viscosity. Therefore, the viscometer is the correct apparatus for determining the consistency of liquid asphalt.
33.
___ is preferable for bituminous prime coat.
Correct Answer
B. Liquid
Explanation
A liquid is preferable for bituminous prime coat because it allows for better penetration and adhesion to the surface being treated. Liquid bitumen can be easily applied and spread evenly, ensuring a uniform and effective prime coat. Solid bitumen would not be suitable as it would not have the necessary fluidity to penetrate and bond with the surface. Blown bitumen is a type of solid bitumen that has been oxidized, making it harder and less suitable for a prime coat. Hot asphalt, while a liquid, is typically used for other applications such as paving and would not be the most suitable choice for a prime coat.
34.
___ is the test used in determining amount of asphalt cement in a liquid asphalt.
Correct Answer
A. Distillation
Explanation
Distillation is the test used to determine the amount of asphalt cement in a liquid asphalt. Distillation involves heating the liquid asphalt and collecting the vapor that is produced. The vapor is then condensed and collected, allowing for the separation and measurement of the asphalt cement. This process is commonly used in the asphalt industry to ensure the quality and consistency of liquid asphalt products.
35.
Are usually tested for extraction.
Correct Answer
C. AspHalt mixes
Explanation
Asphalt mixes are usually tested for extraction. This means that when testing asphalt mixes, the extraction process is typically performed. This process involves separating the asphalt binder from the aggregate in the mix to determine the asphalt content. By testing asphalt mixes for extraction, engineers and researchers can assess the quality and properties of the asphalt binder used in the mix, which is crucial for ensuring the durability and performance of asphalt pavements.
36.
Extraction test is the procedure used for separating
Correct Answer
B. AspHalt from mineral aggregates
Explanation
The extraction test is a procedure used to separate asphalt from mineral aggregates. This process involves dissolving the asphalt in a solvent and then filtering it to separate the asphalt from the aggregates. This test is commonly used in the construction industry to determine the asphalt content in asphalt mixtures and ensure the quality and performance of the asphalt materials used in road construction.
37.
The optimum asphalt content obtained in a marshall stability test is the average of the asphalt content of the maximum stability, maximum density and
Correct Answer
C. 4% air voids
Explanation
In a Marshall stability test, the optimum asphalt content is determined by finding the average of the asphalt content of the maximum stability, maximum density, and 4% air voids. This means that the asphalt content that results in 4% air voids is considered to be optimal. The air voids refer to the empty spaces or pockets within the asphalt mixture, and maintaining a certain percentage of air voids is important for the durability and performance of the pavement. Therefore, the asphalt content that produces 4% air voids is considered to provide the best balance of stability, density, and air voids in the mixture.
38.
____ are intergranular void spaces between aggregate particles.
Correct Answer
A. VMA
Explanation
VMA stands for Voids in Mineral Aggregate, which refers to the intergranular void spaces between aggregate particles. These void spaces are important in asphalt mixtures as they provide room for asphalt binder to flow and coat the aggregates, resulting in a more durable and long-lasting pavement. Therefore, VMA is the correct answer for this question.
39.
The main difference between a bulk measured specific gravity of a bituminous mixtures and its maximum measured specific gravity is the
Correct Answer
C. Volume of voids
Explanation
The main difference between a bulk measured specific gravity of a bituminous mixture and its maximum measured specific gravity is the volume of voids. The bulk measured specific gravity includes the volume of both the asphalt and the voids, while the maximum measured specific gravity only considers the volume of the aggregate particles. By subtracting the volume of voids from the bulk measured specific gravity, the maximum measured specific gravity provides a more accurate measure of the density and compactness of the bituminous mixture.
40.
___ is the best type of asphalt to be used for hot mixes.
Correct Answer
A. AspHalt cement
Explanation
Asphalt cement is the best type of asphalt to be used for hot mixes because it is a pure form of asphalt that is highly viscous and provides excellent binding properties. It is commonly used in hot mix asphalt (HMA) production as it ensures durability, stability, and resistance to weathering. Asphalt cement is also known for its high temperature susceptibility, making it the ideal choice for hot mix applications where high temperatures are involved. Emulsified asphalt, rapid curing, and medium curing cut-back are not as suitable for hot mixes as asphalt cement.
41.
A bituminous coating applied in an existing road prior to laying of a bituminous surface overlay is
Correct Answer
B. Tack coat
Explanation
A tack coat is a bituminous coating applied to an existing road before laying a bituminous surface overlay. It is used to create a bond between the existing pavement and the overlay, ensuring that the new layer adheres properly to the old surface. The tack coat helps prevent slippage and separation between the layers, improving the overall durability and longevity of the road.
42.
The distance traveled by a standard penetration needle on a prepared sample of as[halt under conditions for normal penetration is 8.6mm. The material is ____ penetration grade.
Correct Answer
B. 85-100
Explanation
The distance traveled by a standard penetration needle on a prepared sample of asphalt under conditions for normal penetration is 8.6mm. Based on industry standards, this distance corresponds to a penetration grade of 85-100.
43.
The maximum specific gravity of an asphalt mix containing 6.0% aspahlt by weight of mix is 2.5, if the specific gravity of the asphalt is 1.01, the specific gravity of the aggregate is equal to
Correct Answer
C. 2.76
Explanation
The specific gravity of an asphalt mix is calculated by dividing the weight of the mix by its volume. In this case, the maximum specific gravity is given as 2.5, which means that the weight of the mix is 2.5 times the weight of an equal volume of water. Since the asphalt constitutes 6.0% of the mix, the weight of the asphalt can be calculated as 0.06 times the weight of the mix. Given that the specific gravity of the asphalt is 1.01, the weight of the mix can be calculated as (2.5/1.01) times 0.06 times the weight of the mix. Solving this equation gives a specific gravity of the aggregate equal to 2.76.
44.
A job-mix formula provides for close control of
Correct Answer
C. Both of them
Explanation
A job-mix formula is a predetermined blend of aggregates and asphalt binder that is used in the production of asphalt mixtures. It is designed to provide the desired properties and performance of the asphalt pavement. By specifying the aggregate gradation and asphalt content in the job-mix formula, close control can be achieved over both of these factors during the asphalt production process. This ensures that the resulting asphalt mixture meets the required specifications and performs optimally in terms of durability, strength, and resistance to cracking and rutting.
45.
The desired property of fresh concrete is
Correct Answer
C. Workability
Explanation
Workability refers to the ease with which fresh concrete can be mixed, transported, placed, and compacted without segregation or excessive bleeding. It is an important property as it determines the ease of construction and the ability to achieve the desired shape and finish of the concrete. A concrete with good workability is easier to handle and manipulate, allowing for better compaction and reducing the risk of defects or voids in the final structure. Therefore, workability is a desired property of fresh concrete.
46.
The sieve used in the separation of aggregates after the abrasion test is
Correct Answer
A. 1.70mm #12
Explanation
The correct answer is 1.70mm #12. This sieve size is used in the separation of aggregates after the abrasion test. The sieve has a mesh size of 1.70mm, which means that it allows particles smaller than 1.70mm to pass through while retaining larger particles. This sieve size is commonly used in the construction industry to determine the particle size distribution of aggregates, which is important for evaluating their suitability for various applications.
47.
Normally, concrete mix with __ water-cement ratio will develop the lowest strength
Correct Answer
A. 0.75
Explanation
A concrete mix with a higher water-cement ratio will have a lower strength. This is because excess water in the mix leads to more voids and weakens the overall structure. A water-cement ratio of 0.75 indicates a higher proportion of water compared to cement, resulting in a weaker concrete mix.
48.
The most important single factor which affects the quality of concrete is
Correct Answer
C. Water-cement ratio
Explanation
The water-cement ratio is the correct answer because it is a crucial factor that determines the strength, durability, and workability of concrete. The ratio refers to the amount of water used in proportion to the amount of cement in the mixture. A higher water-cement ratio can result in weaker and more porous concrete, while a lower ratio can lead to a stronger and more durable material. Therefore, controlling and maintaining an appropriate water-cement ratio is essential for achieving high-quality concrete.
49.
Paving concrete will need less ____ than that of structure concrete.
Correct Answer
D. Both a and b
Explanation
Paving concrete will need less sand and water compared to structural concrete. This is because paving concrete is typically designed to have a lower water-to-cement ratio and a lower sand content, allowing it to be more workable and easier to place. Additionally, paving concrete is often subjected to less stress and load compared to structural concrete, so it requires less coarse aggregate for strength. Therefore, both sand and water are needed in lesser quantities for paving concrete.
50.
Concrete specimen molded in a 6"x6"x21" beam should be rodded
Correct Answer
D. 63
Explanation
When molding a concrete specimen in a 6"x6"x21" beam, it is necessary to rod the concrete. Rodding refers to the process of using a rod or vibrator to remove air bubbles and ensure proper compaction of the concrete. This is important because trapped air can weaken the concrete and lead to structural issues. Therefore, the correct answer is 63, indicating that rodding is required for this type of concrete specimen.