Explanation: The bearing capacity of a soil is influenced by factors such as the size of the footing. The larger the footing, the more it can distribute the load and, therefore, affect the bearing capacity.
Explanation: For waterlogged soil, improving drainage can enhance its bearing capacity. Proper drainage helps reduce excess water content, making the soil more stable and capable of supporting loads.
Explanation: Black cotton soil exhibits volumetric changes, swelling significantly when wet and shrinking excessively when dry. These characteristics make it crucial to consider in construction.
Explanation: Unlike draining sub-soil water or ramming crushed stone, watering the surface of the soil does not contribute to improving its bearing capacity.
Explanation: The grain size of the soil is a key factor influencing the bearing capacity. Different soil types with varying grain sizes exhibit different bearing capacities.
Explanation: The safe bearing capacity is the maximum load intensity that the soil can safely support without undergoing excessive settlement or failure.
Explanation: The bearing capacity typically increases with a larger footing area, as it helps distribute the load over a larger surface area.
Explanation: The self-weight of the footing is not considered in calculations for upward soil pressure or while determining the area of the footing.
Explanation: The depth of foundation is determined based on the bearing capacity (B.C.) of the soil, ensuring that the foundation extends to a depth where the soil can support the structure effectively.
Explanation: Under rammed piles are typically bore piles, formed by driving a casing into the ground and then filling it with concrete after removing the casing.
Explanation: The geologic cycle for soil formation involves weathering of rocks, transportation of soil particles, deposition, and finally, upheaval or uplift.
Explanation: A plate load test is conducted to determine both the bearing capacity and settlement characteristics of the foundation soil.
Explanation: Undisturbed soil samples are best obtained using thin-wall samplers, ensuring minimal disturbance to the soil structure during extraction.
Explanation: Westergaard analysis is commonly used for analyzing the bearing capacity of cohesive soils.
Explanation: A shallow foundation is characterized by a depth of embedment that is less than its width, making it suitable for structures with relatively low loads and causing less settlement.
Explanation: Black cotton soil is an example of cohesive soil, characterized by its high clay content and the ability of its particles to stick together.
Explanation: The settlement of a soil is directly proportional to the depth of compressible soil strata and the compression index, which reflects the compressibility characteristics of the soil.
Explanation: The maximum permissible value of dry density is referred to as zero air voids, saturation dry density, and simply dry density, depending on the context.
Explanation: Sedimentation analysis assumes that soil particles are spherical, settle independently of other particles, and the wall of the jar does not affect the settlement process.
Explanation: The permissible tension on the soil under footings subjected to combined compression and bending is typically considered zero to prevent tensile failure in the soil.
Explanation: Combined footings are generally used when there are two columns, and they are spaced close to each other, requiring a common footing for stability.
Explanation: In a row of columns, strip foundations are commonly used to support multiple columns along a linear path.
Explanation: A strap footing involves a cantilever beam connecting two individual footings to improve load distribution and foundation stability.
Explanation: Individual footings under a strap footing are connected by a strap beam, which helps distribute loads between them.
Explanation: Grillage foundations are suitable for transferring heavy loads and are often used in structures with high load-bearing requirements.
Explanation: Pier footings are suitable for supporting heavy structures in sandy soil, providing concentrated support points.
Explanation: Foundations are placed below ground level to increase the stability of the structure by providing a secure and robust base.
Explanation: Pile foundations are suitable for supporting structures in waterlogged soils where traditional foundations may not be effective.
Explanation: Raft foundations are preferred when the area required for individual footings is more than 50% of the total area, providing a continuous and stable base.
Explanation: Below a floating foundation, the intensity of pressure is typically equal to the overburden pressure, as the foundation displaces water or soil, causing buoyancy.
Explanation: The statement “all of the above” is true. Clays are generally more prevalent than sands, organic matter in soil can reduce bearing capacity, and aluminous cement may be used in foundations dealing with chemical deposits.
Explanation: The quantity of seepage is proportional to the coefficient of permeability of the soil and the total head loss. Both factors contribute to the flow of water through the soil.
Explanation: Negative skin friction on a pile occurs due to the relative settlement of the soil around the pile. This can lead to additional downward forces on the pile.
Explanation: Negative skin friction reduces the effective capacity of the pile by adding downward forces. This decreases the overall pile capacity.
Explanation: Negative skin friction is more common in friction piles in soft clays. The soft nature of the soil contributes to the development of downward forces on the piles.
Explanation: Skin frictional resistance is caused by both the relative settlement of the soil and the pile. It is the resistance developed along the surface of the pile in contact with the soil.
Explanation: Hard rocks generally have the maximum bearing capacity among the given options. They can withstand significant loads without excessive settlement.
Explanation: Moist clays typically have lower bearing capacity compared to other types of soils. The high water content and compressibility of clays contribute to reduced bearing capacity.
Explanation: For foundations on black cotton soil, replacing the poor soil is a common method to improve bearing capacity. This involves removing the problematic soil and replacing it with better-suited material.
Explanation: The minimum depth of the foundation on clayey soil is typically considered to be 90cm to ensure adequate bearing capacity and stability.
Explanation: The maximum allowable differential settlement for foundations on clayey soils is often limited to 40mm to prevent uneven settling of the structure.
Explanation: The maximum total settlement for isolated foundations on clayey soils is commonly limited to 65mm to control overall settling and maintain structural stability.
Explanation: Foundations in black cotton soils may involve going to a depth where cracks do not extend, limiting loads to 5t/m2, and using trenches filled with sand to minimize direct contact with the problematic soil.
Explanation: Foundations on weaker soils often use raft footings to provide a broader base and distribute the load, reducing the risk of settlement.
Explanation: The maximum permissible eccentricity of load in a rectangular foundation of width ‘B’ is typically limited to B/6 to control the eccentricity and prevent uneven loading on the foundation.
Explanation: Black cotton soil is unsuitable for foundations due to its property of undergoing volumetric changes with changes in moisture content. These changes can lead to settlement and instability.
Explanation: Scaffolding is a temporary rigid structure with platforms used by masons to work at different stages of a building. It provides support for construction and maintenance purposes.
Explanation: Shoring is the arrangement made to support an unsafe structure temporarily. It involves providing additional support to prevent collapse during construction or maintenance.
Explanation: Underpinning is the arrangement of supporting an existing structure by providing supports underneath. It is done to strengthen the foundation or address stability issues.
Explanation: Ashlar masonry involves stones that are chisel-dressed on all beds and joints to create a uniform, perfectly vertical, and horizontal joint. It is a precise and refined form of masonry.
Explanation: For hearthing of thick walls, headers are commonly used. Headers are bricks laid with the short end facing out, providing thickness to the wall.
Explanation: According to thumb’s rule, the width of the wall footing is typically 2t+150, where ‘t’ is the thickness of the wall.
Explanation: Lintels are preferred over arches because arches can be difficult to construct, require strong abutments to withstand thrust, and may need more headroom to span an opening.
Explanation: A brick masonry may fail due to rupture along a vertical joint, shearing along a horizontal plane, or crushing due to overloading.
Explanation: The termination of an unfinished wall in a stepped fashion is known as racking back. This step-like pattern provides a smooth transition for further construction.
Explanation: The work in which bricks are left projecting out in a masonry wall is known as toothing. It facilitates the proper bonding of new construction to existing work.
Explanation: The work of finishing the mortar joints along with the wall construction is known as jointing. It involves creating smooth and well-finished joints between bricks.
Explanation: The operation of finishing the mortar joints after the completion of a masonry wall is known as pointing. It enhances the appearance and durability of the joints.
Explanation: The process of filling hollow spaces of walls before plastering is known as dubbing out. It involves adding additional material to create an even surface.
Explanation: The structure on which an arch rests is called an abutment. Abutments provide support and stability for the arch structure.
Explanation: The number of bricks required for one cubic meter of masonry wall is approximately 560. This can vary based on the size and thickness of the bricks used.
Explanation: Hacking is the process of making the background rough before plastering. It involves creating a textured surface to enhance the adhesion of plaster.
Explanation: A retaining wall can be built using brick masonry, stone masonry, plain cement concrete, or a combination of these materials.
Explanation: The maximum height of a masonry wall that can be constructed in one day is generally around 1 meter. This depends on factors such as weather conditions and workforce.
Explanation: The minimum thickness of the wall where a single Flemish bond can be used is typically 11/2 brick wall. This bond requires a certain thickness for proper construction.
Explanation: The brick laid with its length parallel to the face of a wall is known as a stretcher. It is a common orientation in bricklaying.
Explanation: The brick laid with its breadth parallel to the face of a wall is known as a header. It provides thickness to the wall.
Explanation: The alignment of a cross joint along the plumb line is called a perpend. It is a vertical joint in masonry.
Explanation: The course of stone placed immediately below the cornice along the face of the wall is known as a frieze. It is a decorative element.
Explanation: The minimum width of stretcher bond is 0.5 bricks, header bond is 1 brick, and single Flemish bond is 1.5 bricks, respectively.
Explanation: The main purpose of a cavity wall is heat insulation. The air gap between the inner and outer layers provides thermal resistance.
Explanation: A cavity wall prevents dampness, has a lesser dead load, and provides better insulation for heat and sound.
Explanation: A cavity wall is provided with an air gap between the inner and outer layers.
Explanation: The air space in a cavity wall is not typically filled with material. It remains as an empty space.
Explanation: The inner section of a cavity wall is generally known as the leaf wall. It is the layer that forms the interior surface of the wall.
Explanation: Buttress walls are not primarily designed for taking lateral loads. They are structural supports built against a wall to provide additional strength and stability.
Explanation: When a brick is laid on its side 9 cm x 9 cm with its frog in the vertical plane, it is referred to as “brick on end.”
Explanation: The 9 cm x 9 cm side of a brick as seen in the wall face is generally known as the “header” of the brick.
Explanation: The 9 cm x 9 cm side of a brick as seen in the wall face is generally known as the “stretcher” of the brick.
Explanation: The thickness of joints in the header course should be less compared to the stretcher course for better stability and appearance.
Explanation: A horizontal mortar joint on which masonry units are laid is called the “bed joint.”
Explanation: The cut or broken portion of a brick is called a “bat.”
Explanation: The brick of special shape used in brick masonry is called a “squint.”
Explanation: The part of a brick cut from a whole brick to maintain the bond is known as a “closer.”
Explanation: The portion of a brick obtained by cutting a brick lengthwise into two directions is known as a “queen closer.”
Explanation: The area covered by flat brick soling is approximately 2 times for brick on edge.
Explanation: The ratio of the number of vertical joints in the header course to that of the stretcher course is equal to two.
Explanation: A joint in the masonry parallel to the face of the wall is called a “wall joint.”
Explanation: A joint in the masonry normal to the face of the wall is called a “cross joint.”
Explanation: The slenderness ratio for masonry walls should not be more than 20 for stability and safety.
Explanation: The load-bearing cantilever projection from the face of a masonry wall is called a “corbel.”
Explanation: The part of a wall at the side of an opening in the masonry is known as the “jamb.”
Explanation: The exterior angle between outer faces of a wall is known as a “quoin.”
Explanation: A block of stone placed on a wall or column to distribute the load to the masonry is called a “bed block.”
Explanation: The typical thickness of a bed joint and cross joint in brick masonry is about 10 mm.
Explanation: The normal thickness of an expansion joint in masonry walls must be more than 20 mm for effective expansion relief.
Explanation: Expansion joints in masonry walls are typically provided in wall lengths more than 40 m to accommodate thermal expansion.
Explanation: In brick laying, the tool used for lifting and spreading mortar and for forming joints is a “trowel.”
Explanation: The thickened portion of a masonry wall is called a “pilaster.”
Explanation: The stepped structure provided to provide lateral support for a structure is known as a “buttress.”
Explanation: A guard wall of small height exposed to the weather is called a “parapet.”
Explanation: The allowable clay silt in sand for mortar is typically in the range of 4 to 6%.
Explanation: The preferred cement-sand mortar mix in load-bearing walls is typically 1:6.
Explanation: The preferred cement-sand mortar mix in 1/2 brick walls is typically 1:4.
Explanation: The types of plaster generally used for the ceiling have a cement-sand ratio of 1:3.
Explanation: Lap is the horizontal distance between the vertical joints and is applicable to both stone masonry and brick masonry.
Explanation: An ornamental projection from the face of a brick wall is called a “cornice.”
Explanation: Bricks with one or two edges rounded for use in curved corners are called “bull nose” bricks.
Explanation: Horizontal construction joints in concrete walls are generally provided at soffit level, window sill level, and floor level.
Explanation: The header bond is commonly used in arches.
Explanation: The bond produced by laying alternate headers and stretchers in each course is known as “flemish bond.”
Explanation: In Nepal, the generally used method of bond in masonry wall of brickwork is “english bond.”
Explanation: English bond is often used for carrying heavy loads in brick masonry.
Explanation: For a uniform face appearance, the desired bond in brick masonry is “double flemish bond.”
Explanation: The joint preferred in a single brick wall to save facing bricks is “garden wall bond.”
Explanation: The stretcher bond in brick masonry can be used only when the wall is of half brick thickness.
Explanation: As compared to english bond, the double flemish bond is more compact.
Explanation: The bond in which all courses are laid as stretcher is known as “stretcher bond.”
Explanation: The bond used when bricks are of different thickness is “facing bond.”
Explanation: The bond filled with 4 bats and 1⁄2 closer with the regular header and stretcher is known as “dutch bond.”
Explanation: In ordinary residential buildings, the damp proofing course (D.P.C.) is generally provided at plinth level to prevent rising dampness.
Explanation: D.P.C. stands for damp proof course.
Explanation: Dampness can cause the growth of termites among other issues.
Explanation: In horizontal D.P.C., the thickness of cement concrete (1:2:4) is typically kept at 4.0 cm.
Explanation: The method described is known as membrane damp proofing.
Explanation: Bitumen sheeting is a flexible material used for damp proofing.
Explanation: D.P.C. can be provided in the form of both horizontal and vertical layers.
Explanation: The D.P.C. should be continued and unbroken through the length and thickness of the wall, sealed with bitumen at lap joints, and even at the source of moisture.
Explanation: When D.P.C. is to be laid over large areas, mastic asphalt is a preferred material.
Explanation: Generally, D.P.C. is provided at horizontal level.
Explanation: Bituminous asphalt/asphaltic felt is commonly used as D.P.C. on the horizontal surface.
Explanation: The maximum size of the aggregate used in a damp proof course is typically about 10 mm.
Explanation: The D.P.C. is provided just below the ground floor level for efficiency.
Explanation: Tricalcium silicate is a compound that helps in obtaining early strength of cement concrete.
Explanation: Later stage strength of cement is caused by dicalcium silicate.
Explanation: High alumina cement is specifically designed to resist chemical attacks, including resistance to acid. This type of cement contains a higher percentage of alumina (Al2O3) compared to ordinary Portland cement, making it suitable for applications where resistance to acidic environments is crucial. High alumina cement is commonly used in construction projects where exposure to acidic conditions is anticipated, such as in chemical plants or areas with high sulfate content in the soil.
Explanation: Workability in concrete refers to its ease of handling, placing, and compaction. The addition of certain compounds can enhance workability. Zinc-based compounds, such as zinc stearate or zinc oxide, are often used as workability enhancers in concrete. These compounds act as water-reducing agents, allowing for better dispersion of cement particles and improving the flowability of the concrete mix. As a result, the concrete becomes more manageable during construction.
Explanation: The density of concrete is influenced by the size and density of its aggregates. Generally, as the size of the aggregate increases, the density of the concrete also increases. This is because larger aggregates occupy more space and result in a higher mass per unit volume. However, other factors such as the mix design, water-cement ratio, and air content can also affect the density of concrete.
Explanation: The primary mechanism by which concrete gains strength is through the process of hydration. Hydration is a chemical reaction between cement and water, leading to the formation of crystalline structures that bind the ingredients of concrete together. As the hydration process continues over time, the concrete gradually gains strength and hardness. It is essential to provide adequate curing to allow for proper hydration and achieve the desired strength properties in the concrete.
Explanation: Curing is the process of maintaining adequate moisture, temperature, and time to ensure the proper hydration of cement in concrete. By keeping the concrete surface moist, the hydration reactions continue, allowing the concrete to harden and gain strength. Curing is a critical step in concrete construction, and its duration is essential for achieving the desired durability and performance of the concrete structure.
Explanation: Curing plays a crucial role in the overall quality of concrete. It serves multiple purposes, including reducing shrinkage, preserving the properties of concrete, and preventing the loss of water by evaporation. Properly cured concrete tends to have fewer cracks, improved strength, and enhanced durability. The curing process involves maintaining a suitable environment, often through the application of water or other curing methods, to ensure optimal conditions for continued hydration.
Explanation: Curing methods can vary based on the type of concrete element. For pavements, floors, roofs, and slabs, the ponding method is commonly employed. In the ponding method, a layer of water is retained on the surface of the concrete by forming a shallow pond or reservoir. This water layer helps in maintaining the moisture content necessary for proper curing. Ponding is particularly effective for large horizontal surfaces where other curing methods, such as covering with wet burlap, may not be as practical.
Explanation: Curing contributes to several desirable properties of concrete. It ensures volume stability and strength development, enhances wear resistance, and improves water tightness and overall durability. Adequate curing is essential for achieving the intended performance and longevity of concrete structures. Insufficient curing can lead to various issues, including reduced strength, cracking, and decreased durability.
Explanation: Curing involves maintaining a suitable moisture and temperature environment for the concrete during its early stages of hardening. This can be achieved by wetting the concrete with water through methods like ponding, spraying, or covering with wet materials. In some cases, steam curing may be applied to accelerate the curing process. The goal is to ensure continuous hydration of cement, leading to the development of strength and durability in the concrete.
Explanation: Steam curing is often employed in the mass production of precast concrete elements. Precast concrete elements, such as beams, columns, and panels, are manufactured in controlled environments, and steam curing is applied to accelerate the curing process. Steam curing can lead to faster strength development, allowing for quicker turnover in precast concrete production. It is particularly useful in achieving high-quality precast elements with consistent properties.
Explanation: While steam curing can be beneficial for accelerating the curing of concrete, it is typically not used with rapid hardening cement. Rapid hardening cement is designed to achieve high early strength without the need for accelerated curing methods. Steam curing is more commonly applied to ordinary Portland cement or other types of cement to achieve specific strength requirements in a shorter time frame.
Explanation: Concrete using rapid hardening cement often requires a shorter curing period compared to other types of cement. Rapid hardening cement is formulated to gain strength rapidly, allowing for faster demolding, formwork removal, and earlier use of the concrete structure. However, it’s essential to follow recommended curing practices to ensure that the concrete attains the desired long-term strength and durability.
Explanation: The compaction factor test is a method used to assess the workability of concrete mixes with low water-cement ratios. Workability refers to the ease with which concrete can be mixed, placed, and compacted. The compaction factor test involves measuring the degree of compaction achieved by a concrete mix under standardized conditions. A higher compaction factor indicates better workability for the given mix, even with a lower wate cement ratio.
Explanation: The compaction factor is a dimensionless value that represents the degree of compaction achieved by a concrete mix. A compaction factor of 0.95 suggests a medium level of workability. It indicates that the concrete mix can be easily compacted, but it may not be as fluid or easily flowable as mixes with higher compaction factors. The interpretation of compaction factor values is relative, and the suitability of the workability depends on the specific requirements of the construction project.
Explanation: The slump test is a widely used method for assessing the consistency or workability of fresh concrete. During the test, a truncated cone-shaped concrete specimen is molded, and the slumping of the concrete is observed after the removal of the mold. The extent of slumping provides an indication of the consistency of the concrete mix. A higher slump indicates a more workable and fluid mix, while a lower slump suggests a stiffer mix. The slump test is valuable for ensuring that the concrete mix meets the desired consistency for proper placement and compaction during construction.
Explanation: In the slump test, each layer of concrete is compacted by rodding with a steel rod. The standard procedure involves rodding each layer of the concrete specimen 25 times. This helps in achieving proper compaction and ensures consistent results in assessing the workability of the concrete mix.
Explanation: The slump value is a measure of the workability of concrete. In this context, a slump of 60mm indicates medium workability. Workability refers to the ease with which concrete can be mixed, placed, and compacted. A slump of 60mm suggests that the concrete mix is moderately easy to work with, and it possesses a balance between fluidity and cohesiveness.
Explanation: Different concrete applications require varying degrees of workability. For beam and slab elements in reinforced concrete construction (RCC), a slump range of 50-100mm is commonly recommended. This range ensures that the concrete mix has sufficient fluidity to flow and fill the formwork adequately while maintaining the necessary cohesiveness.
Explanation: The slump test is primarily used to assess the workability of fresh concrete. It provides information about the consistency and flowability of the concrete mix, helping to ensure that the mix can be easily handled, placed, and compacted during construction. While the test indirectly reflects some aspects of concrete strength, its main purpose is to evaluate workability.
Explanation: Concrete typically gains approximately 40% of its ultimate strength at the age of three days. The early strength development is crucial for demolding and formwork removal in construction activities. However, it’s essential to note that the concrete continues to gain strength over an extended period, reaching higher percentages at later ages.
Explanation: The approximate ratio of the strength of cement concrete at 7 days to that at 28 days is around 0.65. This means that concrete gains a significant portion of its strength within the first 7 days, and the strength continues to increase up to 28 days of curing. The specific ratio may vary based on mix proportions and curing conditions.
Explanation: Concrete is generally considered to have achieved its full strength potential at the age of twenty-eight days. The strength gained by concrete at this stage is often used as a reference point for assessing the quality and performance of the concrete mix. While further strength development may occur beyond twenty-eight days, the rate of gain diminishes.
Explanation: The approximate ratio of the strength of cement concrete at 3 months to that at 28 days is around 1.15. This ratio reflects the continued strength development of concrete beyond the initial 28 days of curing. Concrete structures often experience ongoing improvement in strength and durability over extended periods.
Explanation: The approximate ratio of the strength of a larger concrete cube (30 cm) to that of a smaller cube (15 cm) is around 1.10. This ratio is influenced by factors such as the size effect and the distribution of aggregate particles within the concrete mix. Generally, larger concrete specimens tend to exhibit slightly higher strengths compared to smaller specimens.
Explanation: The approximate ratio of the strength of cement concrete at 6 months to that at 28 days is around 1.2. This indicates that concrete continues to gain strength beyond the initial 28 days of curing. The specific ratio can vary based on factors such as mix design, curing conditions, and the type of cement used.
Explanation: The approximate ratio of the strength of cement concrete at 1 year to that at 28 days is around 1.30. This signifies the continued long-term development of strength in concrete. The ratio may vary based on several factors, and the specific requirements of a project determine the importance of the strength achieved at different ages.
Explanation: The size of fine aggregates in concrete is typically specified based on the maximum particle size. The commonly accepted maximum size for fine aggregates is 4.75 mm (or No. 4 sieve size). This ensures that the fine aggregates are suitable for various concrete applications, providing a balance between workability and strength.
Explanation: Concrete experiences shrinkage as it dries and loses moisture over time. The maximum shrinkage takes place after drying for an extended period, typically around one year. This long-term shrinkage is attributed to the continued moisture loss and structural adjustments within the concrete matrix.
Explanation: Shrinkage in cement concrete is influenced by factors such as moisture content. The shrinkage decreases when moisture is added or when the concrete is kept in a moist environment. Adequate curing and moisture retention during the early stages of concrete development can help minimize shrinkage and enhance the overall durability of the structure.
Explanation: Rounded aggregates generally have fewer voids when compacted compared to irregular, angular, or flaky aggregates. The shape of aggregates can influence the workability and density of concrete. Rounded aggregates facilitate better compaction and result in concrete with reduced voids, contributing to improved overall performance.
Explanation: Workability of concrete is influenced by the shape of aggregates. Rounded aggregates provide better workability for a given water content. The smooth surfaces of rounded aggregates allow them to move more freely, resulting in a more fluid and workable concrete mix.
Explanation: An excess of flaky particles in concrete aggregates can have several adverse effects. It may increase the quantity of water and sand needed in the mix, negatively impact the durability of concrete, and concentrations exceeding a certain percentage (commonly more than 15%) are generally considered undesirable.
Explanation: An aggregate is considered elongated if its greatest dimension (length) is greater than nine-fifths of the mean size. Elongated particles can adversely affect the workability and strength of concrete and may lead to issues such as poor compaction.
Explanation: An aggregate is classified as flaky if its least dimension is less than three-fifths (3/5) of the mean dimension. Flaky particles are undesirable in concrete as they can result in a less workable mix and contribute to weaknesses in the hardened concrete.
Explanation: An excess of thin, flat, or elongated particles in concrete aggregates can reduce workability. Thin particles may increase the water demand, flat particles can lead to segregation, and elongated particles may hinder proper compaction. Therefore, a balanced aggregate shape is crucial for achieving good workability.
Explanation: The grading of sand, which refers to the distribution of particle sizes, can significantly impact various properties of concrete. It influences workability, strength, and durability. Properly graded sand helps achieve a well-balanced concrete mix with desirable properties.
Explanation: Gap grading in a grading curve is represented by a horizontal line. Gap grading occurs when certain particle sizes are absent or sparsely represented in the aggregate gradation. This can affect the workability and stability of the concrete mix.
Explanation: The correct statement is that in single size aggregates, bulk density is least. Properly graded aggregates with a mix of different particle sizes tend to have higher bulk density. Single size aggregates, where all particles are of the same size, have lower bulk density due to increased void spaces.
Explanation: The bulk density of aggregates depends on various factors, including the shape of particles, the grading (distribution of particle sizes), and the compaction method. The arrangement and packing of particles influence the overall bulk density of the aggregate.
Explanation: The bulk density of aggregates is commonly expressed in kilograms per liter (kg/liter). It represents the mass of aggregates per unit volume. The specific units may vary, and other common expressions include kilograms per cubic meter (kg/m³) or grams per cubic centimeter (g/cm³).
Explanation: The risk of segregation in concrete is influenced by various factors, including a wet mix, coarse grading of aggregates, and a larger proportion of the maximum size aggregate. A wet mix can lead to bleeding, and an uneven distribution of coarse aggregates may result in segregation during transportation and placement.
Explanation: Rounded spherical aggregates, by their nature, tend to have fewer voids when compacted compared to irregular or flaky aggregates. The shape of aggregates plays a crucial role in the packing density and overall performance of concrete.
Explanation: The coefficient of variation (CV) is calculated as the ratio of the standard deviation to the mean (average) compressive strength, expressed as a percentage. In this case, (500/4000) * 100 equals 12.5%. The coefficient of variation provides a measure of the relative variability or dispersion of the compressive strength values.
Explanation: Batching error refers to inaccuracies in the quantity of various ingredients in the concrete mix. It can involve errors in measuring aggregates, cement, water, or any other components. Accurate batching is crucial to ensure the desired properties and performance of the concrete.
Explanation: Bulking of sand refers to the increase in volume or swelling of sand particles when they are saturated with water. The presence of moisture causes the sand particles to separate and occupy a larger volume, affecting the accurate measurement of sand in a moist condition. This phenomenon is important to consider during concrete mix design to account for the bulking effect when determining the correct proportions.
Explanation: Graded aggregates, where the sizes of particles are distributed in a well-graded manner, are commonly used to ensure the quality of concrete. Proper grading helps in achieving a dense and workable concrete mix with improved strength and durability.
Explanation: The allowable shear stress of concrete depends upon its shear strength. Shear strength is an important property of concrete in resisting forces acting parallel to the surface. It is influenced by factors such as concrete mix design, curing conditions, and the presence of reinforcement.
Explanation: The permissible compressive strength of M 150 concrete grade is 150 kg/cm2. Concrete grades are specified based on their compressive strength, and M 150 indicates a mix design with a characteristic compressive strength of 150 kg/cm2.
Explanation: Gypsum is added to cement during the manufacturing process to control the setting time. It acts as a retarder, slowing down the setting of cement. This is important for providing sufficient time for concrete placement and finishing.
Explanation: The cement becomes compromised and less effective if its absorbed moisture content exceeds 5%. Excessive moisture can lead to clumping and affect the performance of the cement in concrete applications.
Explanation: The strength of cement tends to decrease with the passage of time. This is particularly true if cement is improperly stored, exposed to moisture, or if it ages over an extended period.
Explanation: The strength of concrete generally increases with the passage of time due to the ongoing hydration process. Proper curing and adequate time allow the concrete to gain strength and achieve its design compressive strength.
Explanation: An aggregate is known as a cyclopean aggregate if its size is more than 75 mm. Cyclopean aggregates are larger-sized aggregates commonly used in mass concrete constructions.
Explanation: Saturated surface dry (SSD) aggregate refers to aggregates that have absorbed moisture into their pores but have a dry surface. SSD condition is commonly used in concrete mix design to account for the water content absorbed by aggregates.
Explanation: The Los Angeles machine is used to test the abrasion resistance of aggregates. The test involves subjecting aggregates to abrasion, impact, and grinding actions to determine their resistance to wear and tear.
Explanation: The fineness modulus (FM) is a measure of the fineness or coarseness of sand. A fineness modulus of 2.5 indicates fine sand. The classification ranges from very fine sand (lower FM) to coarse sand (higher FM).
Explanation: To obtain aggregates with a fineness modulus (FM) of 5.4, a combination of aggregates with different FM is required. In this case, the percentage of aggregate with FM 2.6 to be combined with coarse aggregate (FM 6.8) is 50%.
Explanation: The moisture content of aggregates can be determined by both the displacement method and the drying method. The displacement method involves measuring the volume of water displaced by the aggregate, while the drying method involves drying the aggregate and measuring the loss of weight.
Explanation: The water-cement ratio can be expressed either as the volume of water to the volume of cement or as the weight of water to the weight of cement. Both expressions are commonly used to specify the water-cement ratio in concrete mix design.
Explanation: The water-cement ratio is generally expressed as the volume of water required per unit weight of cement. A common convention is to express it in terms of the volume of water required for 50 kg of cement.
Explanation: The statement is incorrect. In concrete, a rich mix (higher cement content) generally possesses higher strength than a lean mix. The strength of concrete is influenced by factors such as the water-cement ratio, curing conditions, and the quality of materials.
Explanation: The datum temperature for maturity by Plowman is -11.7°C. Maturity in concrete refers to the total exposure to a combination of time and temperature. It is an indicator of the concrete’s progress towards achieving its ultimate strength.
Explanation: The summation of the product of time and temperature of concrete is referred to as the maturity of concrete. Maturity is a measure that considers the effect of both time and temperature on the development of concrete strength.
Explanation: Higher workability is generally required for concrete structures that are thick and heavily reinforced. Adequate workability ensures that the concrete can flow easily and be properly placed around densely packed reinforcement, reducing the likelihood of voids and achieving good compaction.
Explanation: A concrete mix that causes difficulty in obtaining a smooth finish is known to possess hardness. Hard concrete mixes can be challenging to finish and may require special techniques or additives to improve workability and finishability.
Explanation: The dimensions of a slump mold used in the slump test for concrete are typically 10 cm (top diameter), 20 cm (bottom diameter), and 30 cm (height). The slump test measures the consistency and workability of fresh concrete.
Explanation: Proper proportioning of concrete ensures not only the desired strength and workability but also factors in durability and water tightness of the structure. It involves selecting appropriate ratios of cement, aggregates, and water to achieve the desired concrete properties.
Explanation: The correct formula for calculating the percentage (p) of fine aggregates to combined aggregates based on the fineness moduli is P = (x-z / z-y)x100.
Explanation: The correct ratio of various ingredients (cement: sand: aggregates) in concrete of grade M20 is typically 1:1.5:3. The specific mix proportions may vary based on design requirements and local standards.
Explanation: The correct ratio of various ingredients (cement, sand, aggregates) in concrete of grade M150 is typically 1:2:4. Higher-grade concrete mixes may have different proportions based on design specifications.
Explanation: The ratio of concrete ingredients 1:3:6 corresponds to a lower-grade concrete, typically referred to as M100. Higher-grade concrete mixes have lower water-cement ratios and higher proportions of cement for increased strength.
Explanation: Efflorescence is a deposit of salts that can appear on the surface of masonry walls. While it is related to moisture, it is not a direct source of dampness. The main sources of dampness are rain penetration, rising damp from the ground, and condensation.
Explanation: When designing air-entrained concrete, an allowance for the entrained air is made. Air entrainment is achieved by adding air-entraining agents to the mix, and it is beneficial for improving freeze-thaw resistance and workability.
Explanation: An ideal warehouse is provided with waterproof masonry walls, a waterproof roof, and few windows that remain generally closed. This design helps prevent moisture ingress, ensuring the protection of goods stored inside.
Explanation: The specifications of a cement bag for storage typically include a weight of 50 kg, a height of 18 cm, and a plan area of 3000 sq. cm. These specifications ensure standardization for handling and storage of cement bags.
Explanation: Warehouse pack of cement refers to the pressure compaction of the bags on the lower layers in a warehouse. It ensures that the stored bags are compacted under the pressure of the bags in the upper layers, optimizing storage space.
Explanation: The number of cement bags to be stored can be calculated using the formula: Number of bags = (Effective plan area × Maximum height of piles) / Volume of one bag. Substituting the values, we get (54 m2 × 270 cm) / (50 kg/bag), which is approximately 2700 bags.
Explanation: The maximum number of bags to be stored in two piles can be calculated using the formula: Number of bags = (Length × Breadth × Maximum height of piles × Number of piles) / Volume of one bag. Substituting the values, we get (15 m × 5.6 m × 2.70 m × 2) / (50 kg/bag), which is approximately 2500 bags.
Explanation: Batching is the process of proper and accurate measurement of concrete ingredients (cement, aggregates, water) to achieve the desired uniformity of proportion in the concrete mix. It is a crucial step in ensuring the quality of the concrete.
Explanation: Proper batching ensures not only economy in the use of materials but also contributes to the durability and workability of concrete. It involves measuring and proportioning the ingredients accurately to achieve the desired properties in the finished concrete.
Explanation: The dimensions of a form for measuring 35 liters of aggregates by volume are typically 40 cm in length, 25 cm in breadth, and 35 cm in height. This form is used to ensure accurate measurement during the batching process.
Explanation: The process of mixing, transporting, placing, and compacting concrete using ordinary Portland cement should ideally be completed within 30 minutes. This is to ensure that the concrete remains workable and can be placed and compacted effectively.
Explanation: For concreting of tunnel linings, where the transportation of concrete may involve difficult or confined spaces, concrete is often transported using pumps. Pumps are efficient in moving concrete over longer distances and through intricate structures.
Explanation: To prevent segregation and achieve uniform compaction, the maximum height for placing concrete is typically limited to around 150 cm. Beyond this height, there is an increased risk of segregation and uneven distribution of aggregates.
Explanation: The correct sequence for the removal of formwork is typically from the vertical faces first, followed by the soffit of the slab, and then the soffit of the beam. This sequence helps prevent damage to the concrete structure and ensures safety during the removal process.
Explanation: Seasoned softwood is often suitable for formwork in construction work. Softwood, when properly seasoned, provides the necessary strength and durability required for formwork. It is commonly used due to its availability and cost-effectiveness.
Explanation: The output of a concrete mixer can be calculated by multiplying the number of batches that can be produced in the effective working time by the capacity of each batch. In this case, (7 hours × 60 minutes/hour) / (3 minutes/batch) × 150 liters/batch = 18,900 liters.
Explanation: Too wet concrete can cause segregation, excessive laitance (formation of a thin layer of cement paste on the surface), and lower density. It is important to maintain the correct water-cement ratio to ensure the desired properties of the concrete.
Explanation: Non-uniform compaction of concrete can result in a porous and non-homogeneous structure, leading to reduced strength and durability. Uniform compaction is essential to achieve the desired properties and performance of the concrete.
Explanation: The compaction of concrete improves its density, strength, and durability. Adequate compaction ensures that the concrete mix is free from voids, leading to a denser and more durable finished product.
Explanation: For compacting plum concrete road surfaces with a thickness less than 20 cm, a screed vibrator is commonly used. A screed vibrator is a specialized tool for leveling and compacting freshly placed concrete surfaces.
Explanation: The process of hand compaction of concrete is generally considered inferior to machine compaction. Hand compaction may result in uneven compaction and may not achieve the same level of density and uniformity as machine compaction.
Explanation: ISI (Indian Standards Institute) specifies the full strength of concrete to be measured after 28 days of curing. This is a standard practice in concrete testing, as most of the strength gain occurs during this period.
Explanation: High temperatures can decrease the strength of concrete. Elevated temperatures can accelerate the rate of hydration, leading to rapid setting and reduced strength. It is important to consider temperature conditions during concrete placement and curing.
Explanation: Increased cohesiveness in concrete makes it less liable to segregation. Cohesive concrete has better particle distribution and can resist the separation of aggregates from the mortar during handling and transportation.
Explanation: To produce impermeable concrete, a combination of factors is essential, including thorough mixing, proper compaction, and adequate curing. Each of these factors contributes to achieving a dense and durable concrete with low permeability.
Explanation: The separation of coarse aggregates from the mortar in concrete during transportation is known as segregation. This can lead to uneven distribution of aggregates and affect the quality and appearance of the finished concrete.
Explanation: The separation of water, sand, and cement slurry from freshly mixed concrete is known as bleeding. It involves the migration of excess water to the surface of the concrete, leaving a layer of water on top.
Explanation: Concrete is a composite material consisting of cement, aggregates (such as sand and gravel), water, and optional admixtures. All these components work together to form the hardened and durable material we know as concrete.
Explanation: Cement provides strength, durability, and water-tightness to concrete through the hydration process. The water-cement paste hardens due to hydration, and the cement binds the aggregates together, contributing to the overall strength and durability of concrete.
Explanation: Admixtures in concrete can serve various purposes. Some admixtures accelerate the hydration process, while others can enhance properties such as water resistance or acid resistance. Therefore, all the statements are correct.
Explanation: The maximum percentage of the chemical ingredient in cement is that of lime. Lime is a primary component of cement and plays a crucial role in the hydration process, contributing to the strength of the hardened concrete.
Explanation: The minimum percentage of the chemical ingredient in cement is that of magnesium oxide. While magnesium oxide is present in cement, it is generally present in smaller amounts compared to other components like lime, silica, alumina, and iron oxide.
Explanation: Efflorescence in cement is caused due to an excess of alkalis. When soluble alkalis are present in concrete and react with moisture, they can migrate to the surface and form white, powdery deposits known as efflorescence.
Explanation: Tricalcium silicate (C3S) is known for hydrating rapidly, generating more heat of hydration, and contributing to early strength development. However, it is not more resistant to sulfate attack. Sulfate resistance is typically associated with compounds like tricalcium aluminate (C3A).
Explanation: The rapid hardening of cement is achieved by increasing the lime content, particularly the content of tricalcium aluminate (C3A). This accelerates the hydration process, resulting in higher early strength.
Explanation: Rapid hardening cement is commonly used for road pavements due to its ability to develop high strength at early ages. This allows for faster construction and earlier opening of roads to traffic.
Explanation: Low heat cement is suitable for massive concrete structures like dams because it generates less heat during hydration, reducing the risk of thermal cracking in large and thick sections.
Explanation: Blast furnace slag cement is not typically recommended for thin R.C.C. structures. It is more suitable for use in general construction where slower strength development is acceptable.
Explanation: The commercial names for white and colored cement can vary, and different manufacturers may use different brand names. Colocrete, Rainbow cement, and Silvicrete could be commercial names used in Nepal.
Explanation: Pozzolana cement is manufactured using pozzolanic materials, and the percentage of clay in the pozzolanic material can be up to 30%.
Explanation: Inert material in a cement concrete mix refers to the aggregate, which includes sand, gravel, or crushed stone. Water and cement are the active components in the mix.
Explanation: The bulk density of an aggregate depends on factors such as the size and shape of aggregates, specific gravity of aggregates, and grading of aggregates. It is independent of the size and shape of the container.
Explanation: The water-cement ratio of concrete is given as 0.6, which means that for every 1 kg of cement, 0.6 kg of water is required. Therefore, for 50 kg of cement, the water required is 30 kg (50 kg * 0.6).
Explanation: The water-cement ratio by weight is typically higher than that by volume because the density of cement is less than that of water. The water-cement ratio is a critical parameter in concrete mix design.
Explanation: The standard height of a slump cone used in the slump test for measuring the workability of concrete is 30 cm.
Explanation: The minimum number of test specimens required for finding the tensile strength of concrete is typically 6. This allows for a statistically valid assessment of the material’s properties.
Explanation: The minimum number of test specimens required for finding the compressive strength of concrete is typically 3. However, more specimens may be tested for a more comprehensive evaluation.
Explanation: At the freezing point of water (0°C or 32°F), concrete does not set because the water in the mix freezes, preventing the normal hydration process. Freezing conditions can be detrimental to concrete during the setting and curing stages.
Explanation: The use of sea water in concrete can lead to the corrosion of reinforcement due to the presence of chloride ions. While efflorescence and dampness are also possible issues, corrosion is a significant concern when using sea water in concrete.
Explanation: As the temperature rises, the setting time of cement tends to decrease. Higher temperatures accelerate the hydration process, leading to faster setting times.
Explanation: The water-cement (W/C) ratio in ferrocement is generally kept lower than that in normal concrete. This is done to achieve better workability and prevent excessive bleeding while maintaining the required strength.
Explanation: Troweling is the final operation of finishing floors. It involves using a trowel to smooth and compact the surface of freshly placed concrete.
Explanation: The minimum water-cement ratio required for full hydration of cement is approximately 0.38. This ratio ensures that there is sufficient water for complete hydration of the cement particles.
Explanation: Flash set in ordinary Portland cement paste refers to the phenomenon of premature hardening before normal setting time. It is not a desirable property.
Explanation: The flash set of Portland cement is primarily caused by the rapid reaction of tricalcium aluminate (C3A) with water, leading to premature hardening.
Explanation: The fineness of cement is commonly determined by sieve analysis or air permeability methods. The specific surface area of the cement particles is a crucial factor in assessing fineness.
Explanation: The soundness of Portland cement is determined by the Le Chatelier’s apparatus test. It measures the expansion of cement when subjected to a standard amount of autoclave pressure.
Explanation: The soundness test can indicate unsoundness in cement due to the presence of free lime or excess magnesium oxide. Both factors can lead to expansion and cracking.
Explanation: The maximum permissible concentration of magnesia in ordinary Portland cement is typically limited to around 2% to avoid adverse effects on the properties of the cement.
Explanation: The insoluble residue in cement, often referred to as loss on ignition (LOI), is typically required to be less than 1.5%. This parameter indicates the presence of impurities in the raw materials used for cement manufacturing.
Explanation: The addition of pozzolana to cement can result in increased curing time, reduced heat of hydration, and improved resistance to permeability. Pozzolanic materials like fly ash and silica fume are commonly used for these benefits.
Explanation: Gypsum is added to control the setting time of cement. It acts as a retarder, slowing down the setting of the cement to allow sufficient time for proper placement and finishing.
Explanation: The bulking of aggregates occurs due to an increase in volume caused by the presence of moisture on the surface of the aggregate particles. This increase in volume can affect the mix proportions in concrete.
Explanation: Pozzolana is a siliceous or siliceous and aluminous material that, when combined with lime in the presence of moisture, forms cementitious compounds. It is commonly used as a supplementary cementitious material in concrete.
Explanation: The volume of one bag of cement (50 kg) is approximately 0.0347 cubic meters. This value is based on the density of ordinary Portland cement, which is around 1440 kg/m³.
Explanation: Expansion joints in buildings are generally provided when the length of concrete or structural elements exceeds a certain limit. The common practice is to provide expansion joints for lengths exceeding 45 meters to accommodate thermal movements and prevent cracking.
Explanation: Concrete is commonly reinforced using bars made of mild steel. The use of mild steel reinforcement provides strength and ductility to the concrete, allowing it to withstand tensile forces.
Explanation: The unit weight of Reinforced Cement Concrete (RCC) is commonly taken as 2.5 tons per cubic meter (t/m³). This value may vary slightly depending on the mix proportions and the density of the materials used.
Explanation: In the context of a shutter frame, the vertical side member is referred to as the “style.” The style provides support to the shutter and contributes to the overall structure of the frame.
Explanation: The vertical member running through the middle of a shutter frame is known as the “mullion.” The mullion provides additional support and stability to the frame, especially in the case of larger openings.
Explanation: The projections of the head or sill of a door or window frame, often designed for decorative or functional purposes, are known as “horns.” Horns may be present at the top or bottom of the frame.
Explanation: The maximum thickness of door shutters provided in doors can vary, but a common thickness is 38 mm (approximately 1.5 inches). This thickness provides the necessary strength and durability for typical door applications.
Explanation: A cut or step in the frame of a door to receive the shutter is known as a “rebate.” The rebate provides a space for the door shutter to fit securely and helps in creating a tight seal.
Explanation: The thickness of a rebate is typically kept around 1 cm (10 mm). The precise dimension may vary based on design and construction requirements.
Explanation: A wooden block fixed on the back side of a door frame on its post is known as a “stop.” The stop helps prevent the door from swinging too far into the room and provides support.
Explanation: A wooden block hinged on the post outside a door is known as a “cleat.” Cleats are used to secure doors, especially in the open position, preventing them from swinging too far.
Explanation: A small window in which shutters are allowed to swing around pivots fixed to the window frame is known as a “pivoted window.” Pivoted windows typically open by rotating around a vertical or horizontal axis.
Explanation: The window provided on a sloping roof of a building is called a “dormer window.” Dormer windows are often used to bring light into attic spaces or rooms located within the roof structure.
Explanation: The window provided in a flat roof of a room is known as a “lantern window.” Lantern windows are designed to allow natural light into the space below and may be part of a larger skylight or roof opening.
Explanation: A gate (door) without importance is typically referred to as a “battened & ledged door.” This type of door consists of horizontal battens (boards) held together by vertical ledges. It is a simple and commonly used door design.
Explanation: Bringing the floor to a true level surface by means of screeds is known as “screeding.” Screeds are typically used to level and finish a concrete floor or other surfaces.
Explanation: A floor constructed with special aggregate of 3 mm marble chips mixed with white and colored cement is called a “Terrazzo floor.” Terrazzo flooring is known for its durability and attractive appearance.
Explanation: Cork flooring is suitable for noiseless situations such as theaters, churches, libraries, etc., due to its sound-absorbing properties.
Explanation: Granolithic flooring is suitable to resist heavy wear and provides an attractive appearance. It is a type of flooring made from a mixture of cement, sand, and crushed rock.
Explanation: Timber flooring is preferred for a dancing hall due to its smooth surface and comfortable feel. It is commonly used in areas where a resilient and aesthetically pleasing floor is desired.
Explanation: In stairs, stringers are the sloping members that support the steps (treads) and risers. They provide structural support to the staircase.
Explanation: The arrangement of steps provided from the ground level to the plinth level is known as the “threshold.”
Explanation: In stairs, a flier is a straight step having parallel width of tread. It is a basic step without any change in direction.
Explanation: A series of steps without any platform in a stair is called a “flight.” It represents a continuous series of steps between landings.
Explanation: The number of treads (steps) can be calculated by dividing the total floor height by the riser height. In this case, 2.70 m / 0.15 m = 18 treads. However, the number of risers is one less than the number of treads, so it would be 17 treads.
Explanation: A moulding provided under nosing to beautify the elevation of the step is known as “scotia.” Scotia is a concave moulding used for decorative purposes.
Explanation: The vertical member fixed between steps and handrail in a stair is known as a “baluster.” It provides support and serves as a decorative element.
Explanation: The vertical member provided at the top and bottom ends of a flight supporting the handrail is called a “newel post.” It is a structural element that provides stability to the handrail.
Explanation: The platform at the end of the series of steps is known as the “landing.” It provides a flat surface for users to rest or change direction in the staircase.
Explanation: A bifurcated stair, also known as a split or divided stair, is typically used in modern public buildings. It involves a stair that splits into two branches, usually going in opposite directions, providing separate paths for ascending and descending traffic.
Explanation: A roof sloping in four directions is called a “hipped roof.” It has slopes on all four sides that meet at a common point or ridge.
Explanation: A roof sloping in two directions is called a “gambrel roof.” It has two different slopes on each side, with the lower slope being steeper than the upper slope.
Explanation: A roof sloping in four directions but with a break in slopes is called a “mansard roof.” It has two slopes on each of its four sides, with the lower slope being steeper and often featuring dormer windows.
Explanation: A flat roof is suitable in plains where rainfall is moderate and temperature is high. It provides a simple, horizontal surface.
Explanation: A gambrel roof is suitable in high mountainous regions. Its design allows for shedding snow more effectively.
Explanation: Pitched and sloping roofs are suitable for coastal regions. The slope helps in shedding rainwater effectively.
Explanation: The apex line of a sloping roof is called the “ridge.” It is the highest point where the slopes meet.
Explanation: The wooden piece joining the bottom ends of rafters is called the “eaves.” It extends beyond the supporting wall and provides protection from rain.
Explanation: The line of intersection of the sloping surface of the sloped roof having an internal angle greater than 180° is called the “valley.”
Explanation: The line of intersection of the sloping surface of the sloped roof having an internal angle less than 180° is called the “hip.”
Explanation: The members which support covering materials of a sloping roof are called “rafters.” They are inclined structural members that support the roof covering.
Explanation: The member laid horizontally to support common rafters and transmit the loads to the trusses or wall is called a “purlin.” Purlins provide additional support to the roof structure.
Explanation: Cleats in a roof truss are used to prevent the purlins (horizontal members) from tilting or shifting. They provide additional support and stability to the structure.
Explanation: The roof used in factories is called a “North light roof.” It is a type of industrial roof design that allows natural light to enter the building through north-facing windows or skylights.
Explanation: Domes are preferred for large spans as they provide a structurally efficient way to cover a large area. The dome shape distributes loads evenly, making it suitable for wide spans.
Explanation: The height of the parapet wall is generally kept around 75 cm. Parapet walls are built for safety and to prevent people from falling off the edges of roofs or elevated structures.
Explanation: The minimum height of scaffolding above the floor level is typically kept at 150 cm. Scaffolding provides a safe working platform for construction and maintenance activities.
Explanation: Footings provided at the boundary line are often combined footings. Combined footings support two or more columns and are suitable when columns are closely spaced or near the property line.
Explanation: The minimum width of a load-bearing wall is typically kept at 230 mm. This width ensures the stability and strength of the wall to carry vertical loads.
Explanation: Low water concrete results in non-workability. It becomes difficult to mix and place, affecting the construction process.
Explanation: The water-cement (w/c) ratio is a crucial factor in concrete mix design, and all the mentioned ratios (1:0.3, 1:0.5, 1:0.8) are concerned with the w/c ratio.
Explanation: The water-cement (w/c) ratio for M10 concrete is typically around 0.65. The ratio is adjusted based on the desired strength and workability of the concrete mix.
Explanation: Different types of bonds in brick masonry are used to break vertical joints and provide strength to the wall. Common bonds include English bond, Flemish bond, etc.
Explanation: Damp proofing course is provided along the walls and floor of the building to prevent the rising of dampness from the ground.
Explanation: The filling in cavities with cement slurry is known as grouting. It is commonly used to fill voids and gaps in structures for better strength and stability.
Explanation: In made-up ground with a low bearing power, heavy concentrated loads are generally supported by raft footings. Raft footing distributes the load over a larger area.
Explanation: Hearthling is not typically associated with damp proofing. Surface treatment and guniting are methods used for damp proofing.
Explanation: Auger is not a tool commonly used in laying a brick wall. Trowel, tri-square, and plumb-bob are more commonly used tools in bricklaying.
Explanation: In three weeks’ time, a well-cured cement structure is likely to achieve approximately 90% of its ultimate strength. The curing period contributes to the development of concrete strength.
Explanation: Curing in concrete and cement plaster is a process that helps in gaining early strength. It involves maintaining adequate moisture, temperature, and time to allow the concrete to achieve its desired strength and durability.
Explanation: The earliest period for removing formwork under normal atmospheric conditions is typically 7 days. However, the actual duration may vary based on factors such as the type of concrete and ambient conditions.
Explanation: For a 3 floors high RCC framed residential building, isolated footings are likely to be adopted. Isolated footings support individual columns and are suitable for low to medium-rise structures.
Explanation: Carpet area of a building does not include the area of walls along with doors and other openings, verandah, corridor, passage, bathroom, lavatory, kitchen, and pantry.
Explanation: Bar bending schedule (BBS) is prepared in RCC structure for various purposes, including calculating the quantity of reinforcement, guiding bar benders in construction, and checking the bill of quantities.
Explanation: The height of stone masonry that can be constructed in one day depends on various factors such as the type of stones, bonding pattern, and mason’s skill. The given options represent different possibilities.
Explanation: Lacing in steel structures is provided in two or more section connections. It helps in bracing and providing stability to the structure, especially in compression members.
Explanation: The higher load-carrying capacity of a strut depends on having a larger area of cross-section and a smaller length. This combination increases the strut’s strength and ability to carry loads.
Explanation: The most important test for a stone used in docks and harbors is the weight test. It assesses the stone’s ability to withstand heavy loads, which is crucial in applications where stones are used for construction in marine environments.
Explanation: A through stone should be provided in stone masonry at a distance not exceeding 1.5 meters. Through stones are used to bind the thickness of the wall.
Explanation: A concrete mixer is a device used for mixing concrete manually or mechanically. While there are modern and mechanical mixers, it is a technology used for the manual mixing of concrete.
Explanation: The minimum column size as per the National Building Code of Nepal is typically specified, and it is often in the range of 300 x 300 mm.
Explanation: FAR (Floor Area Ratio) is defined as the ratio of the total floor area of a building to the site area. It is used in urban planning to regulate the size and density of buildings on a given piece of land.
Explanation: The number of risers in a staircase can be calculated using the formula: Number of risers = (Total height of the staircase) / (Height of each riser). In this case, the total height is 3 m, and the height of each riser is not provided.
Explanation: The lightweight spongy concrete, prepared by mixing aluminum in the cement concrete, is called cellular or aerated concrete. It is known for its insulation properties and is used in roof slabs and precast units.
Explanation: First-class bricks, when immersed in cold water for 24 hours, should not absorb water more than 15%. This indicates the resistance of bricks to water absorption.
Explanation: Sukhi is added to lintel mortar to prevent shrinkage. Sukhi is also known as “surkhi,” and it is a powdered material obtained by finely grinding burnt clay bricks. It is added to mortar for better workability and to reduce shrinkage.
Explanation: Gauged mortar, which includes the addition of pozzolanic materials like surkhi or brick powder to lime mortar, is more suitable for construction work in waterlogged areas. It provides better resistance to water.
Explanation: The minimum number of days required for curing freshly laid concrete under normal atmospheric conditions is typically 14 days. Curing is essential for the development of concrete strength and durability.
Explanation: The type of rock suitable for coarse aggregate should be tough to withstand the impact and wear in concrete. Tough aggregates contribute to the strength and durability of concrete.
Explanation: For reinforced cement concrete lintels and slabs, the nominal size of coarse aggregates should not exceed 15 mm. This helps in achieving better workability and a dense concrete mix.
Explanation: Workability increasing admixture is used in concrete to achieve various purposes, including making self-compacting concrete, retaining fluidity, and making concrete pumpable.
Explanation: The slump test of concrete is a measure of its consistency. It indicates the workability of concrete based on the deformation of the concrete mix.
Explanation: Joints provided in wooden floors are often tongue and groove joints. These joints help in maintaining alignment and stability in wooden flooring.
Explanation: Concrete is filled in three layers in a slump cone during the slump test. Each layer is compacted before adding the next layer to ensure accurate measurement of slump.
Explanation: The resistance of an aggregate to compressive force is known as the crushing value. It is a measure of the strength of the aggregate and its ability to withstand crushing loads.
Explanation: The fineness of cement is measured in terms of the surface area in square centimeters per gram of cement. It is an important property affecting the reactivity of cement.
Explanation: Coarse-grained soil contains material bulk density, half of which is larger than 75 microns. This particle size is associated with the fine fraction of soils.
Explanation: All of the statements are correct. Underpinning is the process of strengthening the foundation of an existing building or structure. It may be necessary when the original foundation is not strong or stable enough, or when the usage of the structure has changed. Shoring is the process of temporarily supporting a building, structure, or trench with props.
Explanation: From an earthquake safety perspective, the floor-to-floor wall height of the building should ideally be in the range of 2 to 3 meters. This helps in ensuring stability and resistance to seismic forces.
Explanation: The number of treads in a flight is equal to the number of risers minus one. This relationship holds true in a typical staircase design.
Explanation: The specific yield of soil depends upon various factors, including the compaction of stratum, distribution of pores, and the shape and size of particles. All of these factors contribute to the water-holding capacity of the soil.
Explanation: In three-coat plastering, the third coat serves both as the setting coat and the finishing coat. It provides the final surface finish and contributes to the overall appearance of the plastered surface.