Materials 4

The job mix formula is used to determine the best combination of materials for producing a potentially stable and durable mixture. It considers factors such as the type and gradation of aggregates, the type and amount of asphalt binder, and other additives. By using the job mix formula, engineers can optimize the proportions of materials to achieve the desired performance characteristics of the bituminous mix, such as strength, stability, and resistance to cracking and rutting.

Bulk cement is the correct answer because it refers to a type of cement that is transported and stored in large quantities, typically in silos or bins. It is specifically mentioned in the question that the cement needs to be transferred to an elevated, air tight, and weatherproof storage, which aligns with the characteristics of bulk cement storage. Portland cement and pozzolan cement are types of cement, but they do not necessarily require the same storage conditions mentioned in the question. Therefore, the correct answer is bulk cement.

The consolidation test is usually performed on undisturbed samples. This is because undisturbed samples represent the natural state of the soil, without any disturbance or alteration to its structure. By testing undisturbed samples, the true behavior and properties of the soil can be accurately determined, allowing for more reliable analysis and predictions of its consolidation characteristics. Disturbed samples, on the other hand, have been altered or disturbed during sampling, which may affect their behavior and not provide an accurate representation of the soil's actual properties. Therefore, undisturbed samples are preferred for consolidation testing.

The minimum density of gabion is 1400 kg/cu.m. This means that the gabion must have a minimum mass of 1400 kilograms per cubic meter of volume. This density is important for ensuring the stability and strength of the gabion structure, as a higher density will provide better resistance against external forces and prevent deformation or collapse.

The cohesion and internal friction of soil can be tested using various methods such as the tri axial shear test, direct shear test, and bearing test. These tests help determine the soil's ability to withstand shear forces and provide information about its strength and stability. By conducting all of these tests, a comprehensive understanding of the soil's properties can be obtained, allowing engineers and geotechnical experts to make informed decisions regarding construction projects and soil stabilization techniques.

The minimum thickness of bedding materials beneath the pipe is 100 mm. This is the correct answer because a minimum thickness of 100 mm is necessary to provide adequate support and stability for the pipe. A thicker bedding material would offer even more support, but 100 mm is the minimum requirement. A thinner bedding material, such as 50 mm, would not provide enough support and could lead to instability and potential damage to the pipe.

The tolerance of gabion dimension is +-3% means that the actual dimensions of the gabion can vary by up to 3% from the specified dimensions. This allows for a slight variation in size to accommodate any discrepancies in the manufacturing process or installation. A tolerance of +-3% ensures that the gabion will still be suitable for its intended purpose even if it is slightly larger or smaller than the specified dimensions.

The soundness loss of filed gabion is 9% after 5 cycles. This means that after undergoing 5 cycles, the gabion has experienced a loss in its soundness or stability of 9%. This could be due to various factors such as wear and tear, environmental conditions, or structural weaknesses. It is important to monitor and assess the soundness loss of gabions to ensure their effectiveness in retaining soil or controlling erosion.

The correct answer is 200 mm. This means that the minimum penetration of the preservative into the surface of the timber piles should be 200 mm. This depth ensures that the preservative effectively protects the timber from decay and insect damage. A deeper penetration provides better long-term protection for the timber piles, making them more durable and extending their lifespan.

The specific gravity of magnesium sulfate solution used in the soundness test for aggregate should be within the range of 1.295 to 1.308. This specific gravity range is necessary to ensure accurate and reliable results in the soundness test. A specific gravity outside of this range may indicate an issue with the solution's concentration, which could affect the test's ability to determine the aggregate's resistance to weathering and durability.

Seal coating refers to the process of applying asphaltic material and aggregate to an existing surface in order to create a protective layer that prevents water or surface moisture from infiltrating. This technique helps to prolong the lifespan of the surface by sealing any cracks or gaps that could lead to water damage or deterioration.

The correct answer is 6". When checking the temperature of the mix, it is important to ensure that the thermometer is inserted deep enough into the mix to get an accurate reading. By inserting the thermometer at least 6 inches into the mix, it ensures that the thermometer is submerged in the mix and not affected by the surrounding air temperature. This will provide a more accurate measurement of the mix's temperature.

The correct answer is 150 mm. This means that when excavating the rock, it should be removed to a depth of 150 mm below the subgrade within the limit of the roadbed. This depth is necessary to ensure proper stability and support for the roadbed, allowing for adequate compaction and preventing any potential issues with the underlying rock layer.

According to the given statement, post-tensioning of cast-in-place concrete should not be done until at least 10 days have passed since the concrete was placed. This is because it takes time for the concrete to gain sufficient compressive strength, which is necessary before applying post-tensioning forces. Waiting for 10 days ensures that the concrete has reached the specified strength, making it safe to proceed with post-tensioning.

Marshall stability is the most commonly used method in the design and evaluation of bituminous concrete mixes. This method involves subjecting a compacted cylindrical specimen of the mix to a gradually increasing load until failure occurs. The load at failure, known as the Marshall stability, is a measure of the mix's resistance to deformation and cracking. By determining the Marshall stability, engineers can assess the performance and durability of bituminous concrete mixes, making it an essential tool in their design and evaluation process.

The weight of disturbed samples from hard auger or split spoon should be at least 1 kg. This ensures that an adequate amount of material is collected for testing and analysis. A sample weight of 1 kg allows for accurate determination of properties such as moisture content, density, and particle size distribution. It also ensures that there is enough material available for any additional tests that may be required.

In a bituminous mix, the aggregate that passes the no. 200 sieve is the mineral filler. This is because the no. 200 sieve is used to determine the fineness of the aggregate, and the mineral filler is the finest type of aggregate used in bituminous mixes. Coarse aggregate refers to larger particles, fine aggregate refers to smaller particles, and admixture refers to a substance added to the mix to improve its properties.

The minimum size of galvanized wire mesh is 2.2 mm. This means that the diameter of the wire used to create the mesh should be at least 2.2 mm. Galvanized wire mesh is commonly used in various applications such as fencing, construction, and agriculture. The galvanization process involves coating the wire with a protective layer of zinc to enhance its durability and resistance to corrosion. A minimum size of 2.2 mm ensures that the mesh is strong enough to withstand the intended use and provides adequate protection or containment.

The rate of loading for a concrete cylinder sample subject to a compression test is typically measured in psi/sec. The correct answer in this case is 20-50 psi/sec, which means that the load is applied to the cylinder at a rate between 20 and 50 pounds per square inch per second. This loading rate is important because it affects the strength and behavior of the concrete sample during the test. A higher loading rate can result in higher strength values, while a lower loading rate can lead to lower strength values.

The correct answer is trial mix. The percentage of asphalt to be used in the bituminous mixture is determined through a trial mix. This involves testing different proportions of aggregates and asphalt to find the optimal mix that meets the desired specifications. The trial mix helps in determining the right percentage of asphalt that will provide the desired strength, durability, and other performance characteristics for the specific project.

The correct answer is 0.10 in/min. This means that the movable head of the CBR machine travels at a uniform rate of 0.10 inches per minute.

The slump of workable concrete refers to the measure of its consistency and fluidity. When concrete is vibrated, it tends to settle and compact, causing a decrease in its slump. Therefore, the correct answer is 10-40mm, as this range indicates that the concrete maintains a moderate level of workability while still being able to withstand vibration without excessive settling or compaction.

Clinker is the correct answer because it is a burnt product that is used in the production of Portland cement. It is produced by heating limestone and clay to a high temperature, causing them to fuse together and form small, hard nodules. These nodules are then ground into a fine powder to create Portland cement, which is a type of hydraulic cement. Fly ash and volcanic ash are not directly involved in the production of Portland cement.

The correct answer is 4 because taking multiple measurements in a core sample helps to ensure accuracy and account for any variations in thickness within the sample. By taking more measurements, it is possible to obtain a more representative average thickness of the finish asphalt pavement.

The group index is a test that evaluates the quality of soil as a highway subgrade material. It takes into account various factors such as the plasticity index and liquid limit of the soil. The group index provides a numerical value that indicates the overall suitability of the soil for use in highway construction. A lower group index value indicates better soil quality and higher load-bearing capacity, while a higher value indicates poor soil quality and lower load-bearing capacity. Therefore, the group index is an important parameter in determining the suitability of soil for highway subgrade material.

The correct answer is 7. The blue book provides 7 gradation ranges for hot plant mix bituminous pavement. These gradation ranges are important in determining the size and distribution of aggregates used in the pavement mix. Each range has specific specifications and requirements to ensure the quality and performance of the pavement.

Liquid asphalt is commonly known as cutback asphalt. Cutback asphalt is a mixture of asphalt cement and a petroleum solvent. The solvent is added to make the asphalt more fluid and easier to work with. Once the cutback asphalt is applied, the solvent evaporates, leaving behind a solid and durable asphalt surface. Cutback asphalt is commonly used for road construction and maintenance due to its ease of application and ability to adhere to various surfaces.

The minimum penetration of all piles shall be 3 meters. This means that the piles must be driven into the ground to a depth of at least 3 meters. This requirement ensures that the piles are securely anchored in the soil and can support the load placed on them. A deeper penetration may be required for certain soil conditions or to meet specific engineering requirements, but a minimum of 3 meters is necessary to ensure the stability and strength of the piles.

When the group index is 0, it indicates that the soil is of very good quality. The group index is a measure of the strength and compressibility of the soil, with lower values indicating better quality soil. Therefore, a group index of 0 suggests that the soil is strong and has good load-bearing capacity, making it suitable for construction purposes.

Poorly graded soil refers to a type of soil in which most of the soil grains are of the same size. This means that there is a lack of variation in grain sizes within the soil. This can result in poor drainage and compaction characteristics, as well as reduced stability. Well graded soil, on the other hand, contains a wide range of grain sizes, while gap graded soil has a specific range of grain sizes with gaps in between. Therefore, the correct answer is poorly graded.

The minimum thickness of conventional concrete as the surface course in monolithic pavement is 150 mm. This thickness is necessary to ensure the durability and strength of the pavement surface, as well as to withstand the stresses and loads imposed by vehicles. A thicker surface course provides better resistance to wear and tear, reducing the need for frequent repairs or resurfacing. Additionally, a thicker concrete layer helps to distribute the load evenly and prevent cracking or deformation of the pavement.

The wash loss of fine aggregates in the No. 200 sieve is 3%. This means that when the fine aggregates are washed through the No. 200 sieve, 3% of the material will be lost. This loss can occur due to the smaller particles passing through the sieve openings or getting washed away during the process. It is important to determine the wash loss as it affects the overall quality and gradation of the fine aggregates used in construction.

The dynamic cone penetrometer is an instrument used for rapid in-site measurement of the structural properties of existing road pavement. It is a portable device that measures the penetration resistance of the pavement surface. By driving the cone into the pavement and measuring the depth of penetration, engineers can assess the strength and stability of the pavement. This information is crucial for determining the need for repairs or maintenance on the road. The dynamic cone penetrometer is a cost-effective and efficient tool for evaluating the condition of road pavements.

Cement mixing determines the resistance of the emulsion to break when mixed with mineral aggregate. This process involves combining cement with the emulsion and observing how well they bind together. If the emulsion breaks easily and does not form a strong bond with the aggregate, it indicates a lower resistance. On the other hand, if the emulsion remains intact and forms a strong bond with the aggregate, it suggests a higher resistance. Therefore, cement mixing is a reliable method to determine the resistance of the emulsion to break when mixed with mineral aggregate.

The correct answer is "not more than 2%". In bituminous mixture, the asphalt content is typically 5-8% and the aggregates make up 92-95% of the mixture. Additives are used in small amounts to enhance the performance of the asphalt, but they should not exceed a certain percentage. In this case, the correct answer indicates that the amount of additives should not exceed 2% of the total mixture.

Tack coating refers to the application of liquid asphaltic material on a prepared untreated base. This process helps in bonding the base layer with the subsequent layers, such as asphalt pavement or overlay. Tack coating improves the adhesion and ensures a strong bond between the layers, preventing any separation or delamination. It also helps in sealing the surface and preventing the intrusion of water or other contaminants. Therefore, tack coating is the correct term for this specific application.

Tack coating refers to the process of applying liquid asphaltic material on a prepared untreated base. This is done to create a bond between the base and the subsequent layers of asphalt. Tack coating helps to ensure that the asphalt layers adhere properly to the base, preventing any separation or delamination. It also helps to seal any cracks or imperfections in the base, providing a smooth and durable surface for the asphalt pavement.

Super plasticizer is a type of admixture used in concrete to improve its workability and reduce water content. It allows for a higher water-to-cement ratio, resulting in increased strength of the concrete. The correct answer, 50-70%, suggests that the use of super plasticizer can enhance the strength of concrete by up to 50-70% compared to regular concrete without the admixture.

The correct answer is 50%. When using cement/lime proportions in soil aggregates, the mass of the west soil aggregate should not exceed 50%. This is because exceeding this limit can negatively affect the strength and stability of the mixture. It is important to maintain the right balance of cement/lime and soil aggregate to ensure the desired properties and performance of the final product.

The correct answer is 18 hours. In the soundness test of aggregate, the solution used needs to be cooled to a temperature of 21 + or - 1 deg C and maintained at that temperature for at least 18 hours. This is done to ensure that the aggregate is able to withstand volume changes caused by the reaction between the alkalies in the cement and certain constituents in the aggregate. By cooling the solution and maintaining it at a specific temperature for a certain duration, any potential expansion or cracking of the aggregate can be observed, indicating its soundness.

The correct answer is 1.0 m. When boring in soil, it is necessary to dig to a depth of at least 1.0 m below the proposed gradeline. This depth ensures that the foundation or structure being built will have sufficient stability and support from the soil. Going deeper than 1.0 m may be necessary in certain cases depending on the specific soil conditions and requirements of the project.

When water is added to the soil, it causes the soil grains to separate and expand. This expansion of the soil grains is known as swelling. Therefore, the method used in this scenario is swelling, as the water added causes the soil grains to swell and increase in size.

The plasticity index of a group of soil is determined by the difference between its liquid limit and plastic limit. In this case, since there is no range or values given for the liquid limit and plastic limit, it is not possible to calculate the exact plasticity index. However, based on the given options, the closest value to the average plasticity index of most soils (around 7-8) is 10.

The given answer, "200 tons," is correct because the specifications require one quality test for every 200 tons of asphalt. This means that for every 200 tons of asphalt produced, a quality test needs to be conducted to ensure that the asphalt meets the required standards.

The plasticity index for mineral filler is zero. This means that the mineral filler does not exhibit any plasticity and is not capable of being molded or shaped when wet. It indicates that the mineral filler is non-plastic and will not contribute to the plasticity of a soil mixture.

The unconfined compressive strength test is usually performed on sandy soils because these soils have a higher proportion of sand particles, which provide better drainage and stability. Sandy soils have larger particles with less cohesion, making them more susceptible to compression. By conducting this test, engineers can determine the maximum stress that the soil can withstand without failure, which is important for designing structures and foundations on sandy soil.

The criteria of the material when the soil has a plasticity index value of 10 is silty. This means that the soil has a moderate amount of silt particles, which gives it a certain level of plasticity. Silt particles are smaller than sand particles but larger than clay particles, resulting in a soil texture that is smooth and fine-grained. So, when the plasticity index value is 10, the soil is classified as silty.

The correct answer is "at least 120 deg C". This temperature is necessary to ensure that the bituminous mixture is sufficiently hot and workable for proper placement and compaction. A higher temperature helps to prevent premature cooling and solidification of the mixture, allowing it to be properly spread and compacted before it cools down.

Granular materials are classified as soils where 35% or less of the particles pass through a No. 200 sieve. These materials, such as sand and gravel, have larger particle sizes, which is why they do not pass through the finer mesh of the sieve. This classification is important in determining the soil's drainage properties, compaction, and suitability for construction projects.

The tolerance of mix in bituminous is typically measured in terms of temperature variation. A higher tolerance value indicates a wider range of acceptable temperatures for the bituminous mix. Therefore, a tolerance of 15 deg C means that the bituminous mix can withstand temperature variations of up to 15 degrees Celsius without significantly affecting its performance or quality.