architectural finishes, Doors

Flushing door/Flush door – Types and applications

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Flushing door or flush doors are internal doors with a basic and elegant form, a level surface, and minimum decoration. The door panels are flush with the frame, hence the name “flush door.” Flush doors are popular in modern architectural design because of their clean, minimalist appearance and adaptability.

Doors obstruct or provide access to an entrance or exit to a building, room, or vehicle. Doors are essential for providing security and privacy. They can be made of various materials, including wood, metal, glass, or composites. They come in different forms. Doors are outfitted with a range of hardware such as locks, handles, hinges, and closers. This is to limit access and facilitate smooth operation. The type of door and hardware used depends on the intended purpose and location. For example, residential doors are typically more aesthetically pleasing, while commercial doors prioritize functionality and durability. Doors are essential in building construction and architecture because they can contribute to the overall aesthetics of a room.

This article is about Flush doors and types of flush doors used in building construction and architecture.

What is a flushing door or flush door?

A flush door is an interior door with a smooth, flat surface and no decoration or raised panels. The door panels are flush with the frame, giving the door its name. These doors have a wooden frame with plywood, MDF, or natural wood fixed on both sides. The top surface is finished with laminated sheets, veneers, paint, etc., resulting in a standardized and straightforward appearance. Flush doors are commonly constructed using wood in residential buildings due to their attractive and rich appearance. Poplar, mango, or pine wood can be used to construct the doors.

Flushing doors

Different types of flushing doors

Flush doors are classified into different types. Classification is based on the materials used, the manufacturing method, the finish, and the location of the application.

The following are a few examples of common flush door designs:

  • Solid Core Flush Doors
  • Hollow Core Flush Doors
  • Cellular core flush door
  • Fire-rated flush door
  • Louvered flush door
  • Acoustic flush door

Let us discuss different types of flush doors in detail

Solid Core flushing/flush Doors

The manufacturers sandwich a solid core between two thin sheets of plywood or MDF. The core is made of particleboard, MDF, or solid wood. This construction provides a flush surface on both sides of the door. They then veneer the door with real wood or decorative laminate. These doors typically consist of robust and mineral-based timber and use a variety of materials. The materials they use include blockboard, laminated core, cross band, face wood veneer, and particle board.

This construction method improves the door’s durability and resistance to damage compared to a hollow core door. Solid-core flush doors find frequent use in both residential and commercial structures. This is because of their excellent sound insulation and privacy features.

Solid core flush door

Solid-core flush doors are popular due to their customization options and affordability compared to solid wood doors. Solid core flush doors come in various sizes and styles, including panel and slab options. They can also be purchased with a range of hardware options, including hinges, handles, and locks.

Cellular core flush door

The cellular core flush door comprises a hollow core made up of a honeycomb or grid-like structure. The core is then sandwiched between two thin sheets of plywood or MDF. This creates a flush surface on both sides of the door. This construction method creates a lightweight and cost-effective door that is still relatively sturdy and durable.

The core of cellular core flush doors generally consists of a honeycomb or grid-like structure. The materials used to construct the core include cardboard or engineered wood, such as particleboard, MDF, or plywood. This structure creates a strong, yet lightweight core. The core provides some insulation and sound dampening, although not as much as a solid core door.

Cellular core flush door

Cellular core flush doors are popular in residential and commercial buildings. This is because they are relatively affordable, lightweight, and easy to install. Manufacturers offer a variety of sizes and styles for cellular core flush doors, such as panel and slab designs. Additionally, these doors are painted or stained to match any interior decor.

Doors made with this construction method may not offer the same level of durability or sound insulation as solid-core flush doors. This makes them more susceptible to damage from impacts or moisture. As a result, they are mainly used for interior residential doors rather than high-traffic commercial or industrial settings.

Hollow core flush door

Two thin sheets of plywood or MDF sandwich a lattice or grid-like structure to create a flush surface on both sides of hollow core flush doors, which are a type of interior door with a hollow core. The hollow core makes the door lightweight and easy to handle. This makes them a popular choice for interior doors in residential and commercial settings.

Hollow core flush doors are relatively affordable, and they are available in a variety of sizes and styles, including panel and slab designs. They are also easy to install, and they can be painted or stained to match any interior decor.

While hollow-core flush doors are lightweight and affordable, they do have some limitations. They are not as durable or sound-insulating as solid core or cellular core flush doors. The hollow core can also make them more prone to damage from impacts or moisture. Hollow core flush doors have a lattice or grid-like structure sandwiched between thin plywood or MDF sheets, making them best suited for interior use where sound insulation and durability are not a significant concern.

Fire-rated flush Door

Fire-rated flushing/flush doors withstand fire and smoke for a certain period of time. People typically use them in commercial or public buildings, as well as in multi-family residential buildings where building codes require their installation in areas that require fire resistance.

Manufacturers typically make fire-rated flush doors from fire-resistant materials, including metal, gypsum, or solid core materials like particleboard, MDF, or timber. The doors are often filled with fire-resistant materials Further they are covered with a layer of fire-resistant material, such as sheet metal, gypsum, or special fire-resistant paint.

Fire rated flush door

The rating of a fire-rated flushing door is determined by the length of time it can withstand a fire before it begins to fail. Fire ratings typically range from 20 minutes to 3 hours or more, and the required rating will depend on the building code and the specific application.

Fire-rated flushing doors may also have additional features, such as intumescent strips around the edges or fire-resistant glazing, to help contain fire and smoke. These doors can also be equipped with special hardware, such as self-closing hinges and automatic door closers, to help ensure that the door remains closed during a fire.

Ensuring the correct installation of fire-rated flush doors in accordance with local building codes is crucial to guarantee the required level of protection in case of a fire.

Louvered Flushing Door

A louvred flushing door is a type of interior door that has a series of horizontal slats or louvres inserted into the door panel. The manufacturers can make the louvres from wood, glass, or metal, and they usually fix them in place. However, some designs may permit adjustable louvres.

Louvred flush doors find their usage in areas that require air circulation or ventilation, such as utility rooms or closets. They can also be used in rooms that need privacy or light control, such as bathrooms or bedrooms.

The design of a louvred flush door can vary widely, from traditional styles with solid wood louvres to more modern designs that incorporate metal or glass louvres. They are also available in a variety of sizes and configurations, including single or double doors, and with different hardware options, such as hinges and handles.

Louvered Flushing Door

Manufacturers can make louvred flush doors from various materials, such as wood, MDF, or metal, and they can paint or stain them to match any interior decor. They can also paint or finish the louvres in different colours or textures to add an extra design element to the door.

Overall, louvred flush doors provide a unique combination of ventilation, privacy, and design that make them a popular choice for a variety of applications in residential and commercial buildings.

Acoustic flushing door

People often use acoustic flush doors in commercial settings such as recording studios, theatres, and conference rooms where privacy and sound isolation are important. The manufacturer selects materials with soundproofing properties to construct an acoustic flush door, and they usually build it with a solid core that dampens sound waves.

The name “flush” door comes from its design, which allows it to fit within the plane of the surrounding wall, creating a smooth and seamless surface when closed. This helps to prevent sound from leaking through gaps around the edges of the door.

People often use acoustic flush doors in commercial settings, such as recording studios, theatres, and conference rooms, where they require privacy and sound isolation. Homeowners can also use acoustic flush doors in residential settings, particularly in homes with open floor plans or in rooms where noise levels need to be controlled, such as home theatres or bedrooms.

When selecting an acoustic flush door, it is essential to consider factors such as the sound transmission class (STC) rating, which indicates the door’s ability to block sound, as well as the material used for the door’s core and surface. Proper installation and sealing of the door are also crucial for optimal soundproofing performance.

geotechnical, pile foundation

Driven piles – Features, Types and advantages

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Driven piles support structures and transmit loads to underlying soil or rock, as they are a type of deep foundation used for this purpose. Contractors use driven piles, made of steel, concrete, or wood, to support structures and transmit loads to underlying soil or rock. They also call them displacement piles. The installation of driven piles involves driving them into the ground using impact hammers or vibratory drives until they reach a layer of rock or soil that can support the required loads.

If the soil is exceptionally dense, they may need to pre-drill to ensure the pile reaches the design depth. Construction projects commonly employ driven pile to provide stability and strength to the structure. Driven piles offer a cost-effective deep foundation solution and are commonly used to support buildings, tanks, towers, walls, and bridges.

Why driven piles?

Contractors often use driven piles, which are the most cost-effective deep foundation solution, to support buildings, tanks, towers, walls, and bridges. They are also suitable for embankments, retaining walls, bulkheads, anchorage structures, and cofferdams. Driven piles possess a high load-bearing capacity, durable, and contractors can install them quickly and effectively in various soil conditions. Engineers frequently use them in places with inadequate soil, where conventional shallow foundations would not be strong enough to sustain buildings.

In addition, contractors can install driven piles to support compression, tension, or lateral loads, with specifications determined by the structure’s needs, budget, and soil conditions, making them very versatile.

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Types of driven piles

Driven piles are broadly classified as follows

  • Steel Driven pile
  • Precast Concrete Driven pile
  • Timber pile
  • Composite driven pile

Steel Driven pile

Steel-driven piles support major structures such as buildings, bridges, roads, and industrial facilities in construction. Construction workers push them into the earth using specialized tools like hydraulic hammers or pile drivers until they reach a predetermined depth or a firm layer of rock or soil. Steel-driven piles are steel beams with broad flanges on both ends.

Steel Driven Piles

Steel-driven piles are typically made of high-strength steel with a round or square cross-section. They come in various lengths and widths and can be installed vertically or at an angle to meet foundation design requirements. An impact hammer is used to press the pile into the soil by delivering a forceful blow. For shorter depths, steel screw piles are supported by a cast iron helix and powered by rotary motors.

Because of their durability, strength, and capacity to support enormous loads, the steel-driven pile is a common choice for deep foundations. Steel-driven piles are a cost-effective and quick solution for many construction projects. However, their applicability will depend on factors such as soil characteristics, anticipated loads, and local construction building codes and regulations.

Pre-cast concrete Driven Piles

Precast concrete pile manufacturers deploy these piles in construction to support structures built on weak or compressible soils. They prefabricate these piles in a factory or casting yard before transporting them to the construction site. Based on the project’s unique needs, they can construct precast concrete piles in a vast range of dimensions, forms, and configurations. High-strength concrete, reinforced with steel rebar, is used to make these piles. They often use a vibratory hammer or hydraulic hammer to drive the piles into the earth until they reach the required depth or a solid layer of soil or rock.

Precast concrete Driven Pile

Piles come in a variety of shapes, such as square, octagonal, cylindrical, or sheet. Percussion-driven piles are used in situations where bored piles would be ineffective due to running water or excessively loose soils. They have a load range of 300-1,200 kN and a maximum reach of 30 m. Precast concrete piles are constructed with great accuracy and quality control in a controlled environment, resulting in a consistent and uniform product that satisfies design requirements. They are durable and can withstand adverse weather conditions such as seawater or chemical exposure. Precast concrete piles can also be installed quickly and effectively, saving time.

  • Precast concrete piles are quick to install.
  • They can be used in various soil conditions.
  • Using precast concrete piles saves time and money in construction.
  • Precast concrete piles are durable and reliable.
  • They have high-quality control standards.
  • Precast concrete piles are a popular choice for deep foundation construction.

Timber pile

Timber-driven piles are used in construction to create a stable foundation for structures in weak or compressible soils. Contractors use hammers or pile drivers to create cylindrical or square wood piles from premium softwood species. This type of pile is particularly effective in areas with high water tables where other types of piles may not work as well. Timber-driven piles provide a stable foundation for structures in weak or compressible soils. This is achieved by hammering wooden piles into the ground, which compresses the wood and displaces the surrounding soil. The resulting tight fit helps to support the weight of the structure. Timber-driven piles have the advantages of being inexpensive and simple to install. Nonetheless, they may be susceptible to rot and pest infestation.

timber-driven-piles
timber-driven-pile

Composite driven pile

Engineers commonly use composite piles made of a combination of two or more materials, such as concrete, steel, or timber, when soil conditions require a combination of strength and flexibility. An example of a composite pile is a concrete pile with a steel section, as shown in the figure.

Contractors use composite-driven piles consisting of a steel tube filled with concrete and reinforced with steel rebar because they can withstand heavy loads. They use in various construction projects, such as bridges, high-rise buildings, and marine structures. The steel tube provides structural support and protects the concrete from damage during installation, while the concrete and rebar provide additional strength and stability. Contractors can install composite piles using hydraulic hammers or vibratory drivers to reach depths of up to 60 meters. Due to their durability and corrosion resistance, composite piles are ideal for use in harsh environments.

Quality Control for Driven Piles

The construction of driven piles requires high-quality materials and adherence to standards such as BS 8004:2015 and EC standards. It’s crucial to maintain the pile’s shape and avoid damage during installation and inspect them beforehand for quality assurance. The maximum load a pile can carry depends on soil or rock strata properties, pile dimensions and material, and installation method. Engineers perform load testing on representative samples to determine capacity and use monitoring instruments like inclinometers and settlement gauges to ensure the pile’s sufficient support. Effective quality control and testing are crucial for the safe and reliable performance of driven piles in construction projects.

Driven Pile

During installation, it is crucial to maintain the shape of driven piles and ensure they are not damaged by the installation of subsequent piles.

Quality control of driven piles is an important aspect of ensuring the stability, safety, and longevity of structures that rely on them for support. Here are some of the common quality control measures used for the driven piles.

Pile driving equipment for driven piles

To make sure that piles are installed correctly, trained personnel are required to maintain, calibrate, and operate pile driving equipment properly. Regular inspections are necessary to detect any damage or wear in the equipment, and repairs or replacements must be made promptly.

Pile inspection and testing

Inspect the piles for defects or damage before driving them into the ground. To ensure that the piles have been installed correctly and meet the specified requirements, non-destructive testing methods such as sonic testing or integrity testing should be used to test the piles after installation.

Pile load testing for driven pile

One can conduct load testing of a sample of piles to ensure that they can support the required loads. This involves applying a controlled load to the pile and measuring the resulting deformation, which one can compare to the design specifications to ensure that the piles are safe and reliable.

Pile driving records

One should keep detailed records of the pile driving process, including the number of blows or vibrations required to drive the pile to the required depth, the penetration rate, and any other relevant information. These records are essential to monitor the quality of the installation and identify any issues that may arise during the construction process.

Regular inspections and testing are essential to identifying any issues early in the construction process and enabling prompt corrective action.

Advantages of driven piles

The main advantages are

  • Piles can be pre-fabricated off-site which allows for efficient installation once on-site.

High Capacity

Piles are driven deep into soil or rock. This provides high load-bearing capacity. It’s suitable for supporting heavy structures like buildings, bridges, and marine structures. The process increases the effective length of the pile, resulting in high capacity.

Ease of Installation of driven piles

Compared to other pile types like drilled shafts, the installation of a driven pile is quick and efficient. The installation process involves driving the piles into the ground using an impact hammer or a vibratory driver. This requires minimal excavation and soil removal.

Cost-effective

Other types of foundation systems can often be more expensive than driven piles, particularly when the soil conditions are favourable. The cost-effectiveness of driven piles is due to their relatively simple installation process and the availability of pre-manufactured piles, which can reduce the time and cost required for pile installation.

Minimal disturbance

The installation process of driven piles minimizes the disturbance to the surrounding area, making them suitable for use in urban or environmentally sensitive areas. The piles are driven into the ground, which reduces the amount of soil disturbance and the need for excavation.

Versatility

Driven piles are suitable for a variety of soil conditions, including soft soils, hard soils, and rock layers. They can also be made of different materials such as steel, concrete, and timber, providing a wide range of design options.

  • When driven into the ground, piles displace and compact the soil, resulting in increased bearing capacity. In contrast, other types of deep foundations may require soil removal, which can cause subsidence and structural problems.
  • Installation usually produces little spoil for removal and disposal.

Overall, driven piles offer several advantages in terms of high capacity, speed of installation, cost-effectiveness, minimal disturbance, and versatility, making them a popular choice for foundation systems in many construction projects.

However, the use of driven piles also has some disadvantages, including their relatively high cost compared to shallow foundations, the noise and vibration associated with their installation, and the potential for damage to nearby structures or utilities. Therefore, the selection of driven piles as a foundation type depends on a variety of factors, including soil conditions, load requirements, and site-specific constraints.

Disadvantages of driven piles

In the design and construction process, it is important to consider the disadvantages of driven piles, despite their many advantages. Some of the main disadvantages of driven piles are:

Noise and vibration

The installation of driven piles can generate high levels of noise and vibration. This can be a concern for nearby residents and sensitive structures. Pile driving can cause damage to nearby structures, particularly those with shallow foundations.

Limited depth

Other foundation types may be necessary if the capacity or depth required cannot be achieved with driven piles. This is because of the limitations imposed by soil or rock conditions and the driving equipment’s capacity.

Difficulty in driving through hard soil or rock

Driving piles in hard soil or rock layers can be difficult and time-consuming, which can lead to higher installation costs. Overcoming the hardness of the soil or rock may also require the use of specialized driving equipment or techniques.

Quality Control

The installation of a driven pile requires critical quality control. Poor installation can cause issues such as pile damage, pile movement, or insufficient load capacity. To ensure that the piles are installed correctly and meet the required standards, regular inspection, and testing are required. Moreover, monitoring is necessary during pile installation.

Limited environment suitability

Driven piles may have limited suitability in environmentally sensitive areas. This includes wetlands or areas with a high water table. This is due to the potential soil disturbance caused by the driving process. Moreover, the use of chemicals for the preservation or treatment of piles can have negative impacts on the environment. It is important to consider these factors and explore alternative foundation options in such areas.

Roads, TRANSPORTATION ENGINEERING

Camber in roads – Types of Road Cambers

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Camber in roads is the slope or angle built into the road surface, typically seen on curved or sloped sections of the road. This slope is designed to provide several benefits, including improved drainage, enhanced vehicle stability, and better driver visibility. The purpose of camber on roads is to ensure safe and comfortable driving conditions for motorists.

The slope can be positive, negative, or zero, depending on the specific requirements of the road and the expected traffic flow. The appropriate camber for a road depends on various factors, such as the type of road, its location, and the expected speed and volume of traffic. Proper design and construction of road camber can significantly improve road safety, reduce the risk of accidents, and increase the lifespan of the road surface.

  1. Types of Camber in roads
    1. Positive camber in roads
    2. Negative camber in roads
    3. Zero camber
    4. Composite camber
    5. Sloped camber/straight camber
    6. Two straight-line camber
    7. Barrel camber/Parabolic camber
  2. Significance of road camber
  3. Advantages of Camber on Roads
  4. Recommended Values of Camber in Road For Different Types of Road surface by IRC: 
  5. Disadvantages of excessive road camber

Types of Camber in roads

Camber in roads, or road camber, refers to the slope built into the road surface, typically seen on curved or sloped sections. The road’s camber is usually indicated by the ratio 1:n or as a percentage. Proper camber design and construction are crucial to improve road safety, reduce accidents, and ensure adequate drainage and vehicle stability.

Here’s a list of the types of camber used in road design and construction:

  • Positive camber
  • Negative camber
  • Zero camber
  • Composite camber
  • Sloped or straight camber
  • Two straight-line camber
  • Barrel camber

Positive camber in roads

Positive camber refers to the angle of a vehicle’s wheels where the top of the tire tilts outward from the centre of the vehicle. This can provide improved stability and handle in certain driving situations, such as high-speed cornering. However, excessive positive camber can lead to uneven tire wear and decreased handling performance.

Positive camber

Negative camber in roads

Negative refers to the angle of a vehicle’s wheels where the top of the tire tilts inward towards the centre of the vehicle. This can provide improved grip and handling during cornering, as the tire maintains more contact with the road. However, excessive negative camber can lead to uneven tire wear and reduced straight-line stability.

Negative Camber

Zero camber

Zero camber refers to the angle of a vehicle’s wheels where the tire is perpendicular to the ground and the wheel is vertical. This is considered the ideal angle for tire wear and handling, providing a balance between straight-line stability and cornering grip. Many production vehicles are designed with zero camber for optimal performance and safety.

Composite camber

Composite camber refers to a combination of positive and negative camber on a vehicle’s wheels. In order to achieve optimal handling and performance in specific driving situations, one can adjust the angle of each wheel independently to create a custom setup. This allows for a personalized approach to handling and can be achieved through the use of composite camber. Composite camber is a technique commonly utilized in high-performance vehicles and motorsports to attain maximum grip and control.

Composite Camber

Sloped camber/straight camber

Sloped camber refers to a wheel angle where the tire leans towards the inside or outside of the vehicle, creating a slope. Straight camber refers to a wheel angle where the tire is vertical and perpendicular to the ground. Sloped camber is often used in motorsports to improve cornering performance, while straight camber is more common in street vehicles for better tire wear and handling.

Straight line/ sloped

Two straight-line camber

Two straight-line camber refers to a setup where the camber angle is set to zero for both front and rear wheels. This provides a balanced setup that promotes even tire wear and stable handling. “People commonly use two straight-line camber in street vehicles, SUVs, and pickup trucks, prioritizing comfort, safety, and longevity over high-speed cornering performance.”

Two straight line Camber

Barrel camber/Parabolic camber

“In drifting and racing applications, people commonly use barrel camber to promote tire grip . This in turn improves cornering performance by adjusting the camber angle and toe settings on each wheel independently. Barrel camber is a wheel angle where the center of the tire is lower than the edges, creating a barrel-like shape.”

Barrel Camber or parabolic camber

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Significance of road camber

Road engineers provide camber to promote safe and efficient driving. They use positive camber on curves and turns to offer better stability and prevent vehicles from sliding off the road. On the other hand, they use negative camber on straight sections to enhance tire traction and lower the risk of hydroplaning in wet conditions.

Advantages of Camber on Roads

Camber provides several advantages for road safety and efficiency. “Moreover,” positive camber assists vehicles in remaining centered on the road while turning. This in turn results in decreased skidding and improved stability. Negative camber improves tire contact with the road on straight sections, increasing traction and reducing hydroplaning risk. Camber also helps to reduce tire wear by distributing the load evenly across the tire surface, promoting longer tire life. Overall, camber is a key design feature in road engineering. This helps to promote safe, efficient, and sustainable transportation for all.

Road

The Indian Road Congress (IRC) provides recommended values for camber in road design, based on the type of road surface. These values are as follows:

  1. Flexible Pavement on Earth Embankment
  • Straight: 1.5%
  • Crossfall: 2.5%
  1. Flexible Pavement on Soft Soil
  • Straight: 2%
  • Crossfall: 3.5%
  1. Rigid Pavement on Earth Embankment
  • Straight: 2%
  • Crossfall: 3%
  1. Rigid Pavement on Soft Soil
  • Straight: 2.5%
  • Crossfall: 4%
  1. Bituminous Wearing Course
  • Straight: 1.5%
  • Crossfall: 2.5%

“These values provide general guidance only and depend on local conditions, traffic volume, and other factors. It is important to note that.”

Disadvantages of excessive road camber

Providing excessive road camber height can have several disadvantages. These include:

  • Uneven tyre wear: Excessive camber height can cause the tire to wear unevenly, leading to reduced tire life and increased maintenance costs.
  • Increased fuel consumption: High camber angles can increase rolling resistance and reduce fuel efficiency, leading to higher fuel consumption and greenhouse gas emissions.
  • Reduced braking performance: Excessive camber can reduce the contact area between the tire and the road surface, reducing braking performance and increasing stopping distances.
  • Reduced stability: High camber angles can reduce vehicle stability, especially at high speeds, making the vehicle more difficult to control and increasing the risk of accidents.
  • Uncomfortable ride: Excessive camber can cause the vehicle to ride harshly, transmitting more shocks and vibrations to the occupants, leading to discomfort and fatigue during long journeys.
civil engineering, REINFORCEMENT STEEL

Development length formula as per IS 456

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Development length is an essential concept in civil engineering that refers to the length of reinforcement required to transfer the force from the steel reinforcement to the surrounding concrete. It is crucial in ensuring that the reinforcement is effectively bonded to the concrete to resist the applied forces. “The development length depends on several factors, including the diameter of the bar and the strength of the concrete. “Another factor that affects the development length is the bond strength between the steel reinforcement and the surrounding concrete.”

Properly understanding development length is essential for designing reinforced concrete structures to ensure their safety and stability. Engineers calculate the development length to ensure that the reinforcement will provide the intended strength and reinforcement to the structure. “Insufficient development length can cause the reinforcement to fail to transfer forces to the concrete effectively. This can ultimately lead to structural failure.”

What is the development length?

To develop the full tensile strength of the reinforcement, one must embed the reinforcement in concrete for a minimum length known as the development length. This is necessary to ensure that the reinforcement can resist the applied loads. This should happen without pulling out of the concrete or causing concrete failure.

Either pull-out or splitting failure modes typically control the length. In pull-out failure, the force applied to the reinforcement exceeds the pull-out strength of the concrete. This generally causes the reinforcement to pull out of the concrete. In splitting failure, the force applied to the reinforcement causes the concrete to crack and split. This can lead to the failure of the reinforcement.

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Significance and functions

This is a critical concept in reinforced concrete structures that ensures the effective transfer of forces and prevents premature failure. It is important for the safety and stability of structures and is a crucial factor in their design and construction. The main function is as follows.

Transfer of applied forces

Ensuring effective bonding of the steel reinforcement to the surrounding concrete is the purpose of the Development length in reinforced concrete structures. This allows it to transfer the applied forces to the concrete.

Prevents structural failure:

Basically, the proper bonding of the reinforcement to the concrete prevents premature failure of the structure. This could otherwise result in catastrophic consequences.

Important for design

Properly understanding Develop length is critical for designing reinforced concrete structures. Engineers must calculate the length to ensure that the reinforcement provides the intended strength and reinforcement to the structure.

Basically, an insufficient development length can lead to the reinforcement not being able to transfer the forces to the concrete effectively. However, this results in premature failure and instability.

Structural safety and stability

Generally, this is crucial for the safety and stability of reinforced concrete structures. The failure to effectively bond the reinforcement to the concrete would result in the inability to transfer the applied forces. However, this can lead to structural failure.

Factors determining Development strength

Several factors influence the required development length to fully develop the tensile strength of reinforcement in concrete, including

  • Reinforcement properties: The strength and diameter of the reinforcement significantly impact the required development length. Generally, high-strength reinforcement with a larger diameter will require a longer D length to develop its full strength.
  • Concrete properties: The strength, stiffness, and thickness of the concrete member where we place the reinforcement are crucial factors. However, a higher concrete strength requires a longer d length, while a thicker concrete section may require a shorter length.
  • Bond strength: The bond strength between the reinforcement and concrete is critical in determining the development length. However, the bond strength depends on various factors. This includes the surface condition of the reinforcement, the degree of deformation, and the quality of the concrete surface.
  • Environmental conditions: Environmental factors such as humidity, temperature, and exposure to corrosive agents can affect the bond strength between the reinforcement and concrete. In such cases, we may require a more extended development length.
  • Load conditions: The type, magnitude, and direction of the load applied to the reinforcement significantly influence the development length required. Generally, Higher loads require a longer D length to prevent the reinforcement from pulling out of the concrete.
  • Design codes and standards: Design codes and standards typically provide guidelines for determining the minimum development length required for different types of reinforcement and loading conditions. However, these guidelines may vary depending on the specific code or standard used.

Development length as per IS 456

Basically, Clause 26.2.1 of the Indian code for the design of reinforced concrete structures (IS 456:2000) provides the formula to calculate the development length of reinforcement bars in tension. Basically, we require the length of the reinforcement bar to transfer the stresses between the reinforcement and the surrounding concrete.

The formula for calculating the D length (Ld) of a reinforcement bar with a diameter of D, embedded in concrete with a grade of M, and subject to tension, is as follows:

Ld = (0.87 fy A / 4τ_bd) + (0.2 √fc) …Equation 1

where:

  • fy is the characteristic strength of the reinforcement in N/mm²
  • A is the area of the reinforcement in mm²
  • τ_bd is the bond stress between the reinforcement and the surrounding concrete in N/mm²
  • fc is the characteristic compressive strength of concrete in N/mm²

The first term in Equation 1 represents the basic development length, which is the minimum length required for the reinforcement to fully develop its strength. The second term represents the additional development length due to the curvature of the bar.

It is worth noting that the code also provides alternative methods for calculation, such as the empirical equations given in Table 5 of the code. However, Equation 1 is the most widely used method for calculating the development length in India.

It is important to note that these calculations are based on certain assumptions and simplifications, and the actual development length required may vary based on the specific design requirements and site conditions.

Development length as per IS 456 for columns, footings and beams

The dev. length of rebars is the minimum length required for the effective transfer of forces from the steel reinforcement to the surrounding concrete. However this ensures that the reinforcement is properly bonded to the concrete, preventing premature failure of the structure.

Typical section beam-column junction

Development length of a beam column junction

Development length as per codes

The development length of a reinforcing bar, or rebar, is the minimum length of the bar that must be embedded or overlapped with concrete to ensure proper transfer of stresses between the concrete and steel. This is a critical design parameter, and it is determined based on various factors such as the strength of the rebar, the strength of the concrete, and the design requirements of the structure.

Here are the formulas as per some commonly used codes:

ACI 318-19 (American Concrete Institute)

Ld = [(φ x Fy x As) / (4 x Fc’^(0.5))] x (1.3 for deformed bars, 1.7 for plain bars)

where: Ld = development length in inches

φ = strength reduction factor (0.7 for deformed bars, 0.8 for plain bars)

Fy = yield strength of rebar in ksi

As = area of rebar in square inches

Fc’ = specified compressive strength of concrete in psi

BS 8110-1:1997 (British Standard)

Ld = [(1.2 x σst x As) / (0.87 x Fy x (1 + (200/d))^(0.5))] x (1.4 for deformed bars, 1.7 for plain bars)

where: Ld = development length in mm

σst = stress in rebar at yield in N/mm2

As = area of rebar in mm2 Fy = characteristic yield strength of rebar in N/mm2 d = diameter of rebar in mm

IS 456:2000 (Indian Standard)Ld = [(0.87 x fy x As) / (4 x τbd x fck^(0.5))] x (1.2 for deformed bars, 1.6 for plain bars)

where: Ld = development length in mm

fy = characteristic strength of rebar in N/mm2

As = area of rebar in mm2 τbd = design bond stress in N/mm2

fck = characteristic compressive strength of concrete in N/mm2

It is important to note that the development length calculation may vary based on the specific requirements of the structure, and it is recommended to consult the appropriate code for accurate and up-to-date information.

civil engineering

All cement price list today 2023 – Cement Price per bag today

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All cement price list today is the most important update every construction engineer and civil engineering construction firm should be familiar with. Cement is the most significant and widely used construction material which forms an integral part of any structure. Cement is the major ingredient of concrete and mortar and the structural stability and life of a structure or building depend on the cement quality.

  1. Significance of knowing the price of cement today
  2. Factors affecting the cement prices
  3. Uses of Cement
  4. Top cement companies of India with the latest price list
  5. Conclusion

Significance of knowing the price of cement today

Cement is widely available on the market. Therefore, one needs to be aware of cement’s pricing before purchasing. Cement accounts for almost 20% of total construction costs. Cement is therefore one of the most expensive construction materials. One must therefore be familiar with the most recent cement price list rates that are offered on the market. Generally, cement is utilised for everything from a building’s foundation to its final touches. Because cement prices play such a significant effect on construction costs, it is necessary to consider them when making purchases.

Related posts from vincivilworld

Factors affecting the cement prices

Also, the price of each cement varies according to its quality. Yet, different types of cement are utilised in different locations. The following variables influence cement pricing:

All cement price list today
  • Costs of Raw Materials: The basic raw materials for cement manufacture are limestone and clay, and their prices might fluctuate based on supply and demand situations in their respective markets.
  • Energy Costs: The cost of energy, such as the price of fuel and electricity, can impact cement’s cost.
  • Transportation Costs: The expense involved in transporting raw materials to the manufacturing plant, as well as the cost of delivering the final product to market, can influence cement prices.
  • Production Costs: The cost of production can be influenced by factors such as the cost of labour, the efficiency of the manufacturing process, and the level of competition in the market.
  • Government Regulations: Government rules, such as taxes, import duties, and environmental regulations, can also have an impact on the price of cement.
  • Economic Factors: Generally, economic factors such as inflation, exchange rates, and overall economic growth can all have an impact on cement prices.
  • Market Demand: The level of demand for cement in a particular market can also impact its price. However, during periods of high demand, prices may be higher, while during periods of low demand, prices may be lower.
  • Competition: The level of competition in the cement market can also influence prices. If there is a high level of competition, companies may be pressured to lower their prices in order to remain competitive.
Best Cement of India || Top Cement Companies in India -2021

Uses of Cement

Cement is an essential element in the construction industry. It is needed to make concrete and mortar. Cement is manufactured by heating a mixture of limestone and clay to form a powder. The powder, when mixed with water, makes a paste that sets and hardens. Some of the most common applications for cement are:

  • Cement is used in the manufacture of concrete. Concrete is the major building material for foundations, walls, bridges, and roadways.
  • Masonry work: For laying bricks and stone, cement is used as binding material
  • Plastering: Cement is widely used in the production of plaster. Plaster is used to coat the interior and exterior walls and ceilings of buildings.
  • Cement can be used as a base material in the manufacture of floor screeds, terrazzo, and other flooring products.
  • Dams: It is used in the production of concrete for dams, which are structures designed to retain water.
  • Pipelines: Other subsurface constructions, including pipelines, are made of cement.

In summary, cement is an essential material in the construction industry and is used for a wide range of purposes, from building construction to flooring, and from masonry work to making pipes.

Top cement companies of India with the latest price list

Here is a list of the top cement companies in India along with their latest price list:

  1. UltraTech Cement Ltd. – UltraTech Cement is the largest manufacturer of cement in India and one of the world’s leading suppliers of cement and clinker. As of February 2023, the latest price of UltraTech Cement is Rs. 350 – 400 per bag
  2. Ambuja Cements Ltd. – Ambuja Cements is one of the leading cement companies in India. Ambuja cement is best known for its sustainable practices and use of advanced technology. As of February 2023, the latest price of Ambuja Cement is Rs. 330 -400 per bag
  3. ACC Ltd. – ACC is one of the largest cement companies in India. ACC has a strong presence in the country’s western and southern regions. As of February 2023, the latest price of ACC Cement is Rs. 330 to 450 kg bag.
  4. Shree Cement Ltd. – Shree Cement is a leading cement company in India. We know that Shree cement is known for its high-quality products and innovative business practices. As of February 2023, the latest price of Shree Cement is Rs. 300 – 375 per 50 kg bag.

Please note that these prices may vary based on location and market conditions.

Conclusion

Cement prices play an important part in the cost of every structure. Everyone related to the civil engineering and the construction industry should be familiar with cement prices. Hence it is required to be updated with cement prices regularly. Top brands are available in almost every part of the country.

sheet pile

Sheet pile -Sheet piling types, sheet piling advantages

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A sheet pile is a type of driven pile that uses sections of sheet materials with interlocking edges. We generally install Sheet piles for lateral earth retention, excavation support, and shoreline protection operations. They are typically made of steel, but can also be made of vinyl, wood, or aluminium. Sheet piles are installed in sequence to the design depth along the excavation perimeter or seawall alignment. The interlocking sheet piles provide a wall for permanent or temporary lateral earth support with little groundwater inflow. We use Anchors strategically to provide lateral support Anchors.

We frequently use Sheet piles for seawalls, retaining walls, land reclamation, and underground constructions. Underground constructions include parking garages, and basements, in marine locations for riverbank protection, seawalls, cofferdams, and so on.

  1. Sheet piling method
  2. Sheet piles – Applications
    1. Retaining walls
    2. Coastal protection:
    3. Cofferdams:
    4. Underground structures
  3. Advantages of sheet pile
  4. Sheet piling types
    1. Steel Sheet piles
    2. Vinyl sheet pile
    3. Wooden sheet pile
    4. Features of wooden piles
    5. Concrete sheet pile
    6. Aluminium sheet piles
    7. Composite sheet piles
    8. Cellular sheet pile
    9. Cold-formed sheet piles
  5. Conclusion

Sheet piling method

Sheet piles can be temporary or permanent. Permanent steel sheet pile design demands a long service life. Often we install Sheet piles using vibratory hammers. If the earth is too hard or dense, we perform the installation with an impact hammer. Hot-rolling and cold-forming are the two major methods for creating sheet piles. Manufacturing of Hot rolled piles takes place at high temperatures, and the interlocks appear to be stronger and more durable.

We install Sheet piles by driving them into the ground with an impact hammer or vibratory driver and connect them to one another by a number of interlocking mechanisms. This includes tongue-and-groove, hook-and-grip, and clutch-bolt connections. Sheet piles, once erected, form a continuous barrier that resists lateral pressure from soil or water, avoiding soil erosion, landslides, and other soil failures.

sheet piles

Sheet piles – Applications

Piles find frequent utilisation in the following construction projects:

Retaining walls

Sheet piles help to construct retaining walls that hold back soil or water while also providing lateral support for excavations.

Coastal protection:

Sheet piling can protect coastal areas from erosion, waves, and storm surges. They can also be used to construct breakwaters and jetties.

Cofferdams:

We use Sheet piles to build cofferdams, which are transient obstructions in water to facilitate the construction of piers, bridges, or other water-based constructions.

Underground structures

We use Sheet piles to construct underground constructions such as basements or underground parking garages. They support the lateral structure and restrict soil or water intrusion.

Sheet piles have various advantages, including their versatility, ease of installation, and durability. Moreover, they offer an affordable option for projects that need lateral earth support. However, adequate design and installation are essential for guaranteeing the sheet pile wall’s stability and safety.

Advantages of sheet pile

Sheet piles provide several advantages in construction projects that require lateral earth support. Following are some of the key benefits of sheet piles:

  1. Versatility: Sheet piles find applications in a variety of construction projects, including retaining walls, shoreline protection, cofferdams, and underground structures.
  2. Speed of installation: We can install Sheet piles quickly and efficiently using impact hammers or vibratory drivers, which can reduce project timelines and construction costs.
  3. Durability: Since the material of construction Sheet piles is steel or other durable materials that can withstand harsh environmental conditions, including exposure to water, corrosion, and extreme temperatures, they are highly durable.
  4. Cost-effectiveness: Sheet piles generally prove to be a more affordable alternative to other types of foundation systems for projects requiring lateral earth support since they need less excavation and backfilling.
  5. Minimal disturbance: Sheet pile installation creates minimal disturbance to the surrounding soil and structures since we drive the piles into the ground without the need for excavation or other site preparation.
  6. Reusability: Sheet piles offer easy removal and reuse in other projects, making them a sustainable and eco-friendly alternative.
  7. We use Sheet piles for temporary and permanent structures and are available in a wide range of lengths, sizes and steel options.
  8. We can install Sheet piles rapidly using silent and vibration-free methods. The installation is easier and faster than secant walls.
  9. We can construct Cofferdams in almost any desired shape. Provide a close-fitting joint to form an effective water seal. Joints are designed to withstand the high pressure necessary for them to be placed in place. A little maintenance is needed above and underwater
sheet piling

Sheet piling types

Sheet piles are broadly classified as follows based on the material used for driving.

  • Steel sheet pile
  • Vinyl sheet pile
  • Wooden sheet pile
  • Concrete sheet pile
  • Composite sheet piles
  • Cellular sheet pile
  • Cellular sheet pile
  • Cold-formed sheet pile

Steel Sheet piles

Steel sheet piles are long, thin sections of steel that are driven into the ground to construct a retaining wall or a barrier. The most popular material for sheet piles is steel since we can lengthen it either by welding or bolting and has great water tightness as well as good resistance to severe driving stresses. They find extensive applications in civil engineering and construction projects to provide structural support for excavations, bridges, highways, and other structures.

Steel sheet piles are primarily made of hot-rolled steel and are available in a variety of shapes and sizes. We can link them together to form a continuous wall that acts as a strong barrier against the soil or water pressure. Steel sheet piles should endure heavy loads and give structural stability. Corrosion prevention techniques including coating and cathodic protection help increase the durability of steel sheet pile.

We frequently use Steel sheet piles in foundation work and deep excavations because they offer high resistance to lateral stresses and enable quick and simple installation. They are an eco-friendly option for temporary constructions because we can recycle them.

Overall, steel sheet piles are a versatile and cost-effective solution for a wide range of civil engineering and construction projects.

There are four basic forms of steel sheet piles, Normal sections, Straight web sections, Box sections and Composite sections.

Vinyl sheet pile

A vinyl sheet pile is a form of plastic sheet pile that finds applications in civil engineering and construction projects for a variety of purposes such as seawalls, bulkheads, flood walls, and retaining walls. Vinyl sheet pile primarily comprises polyvinyl chloride (PVC), a lightweight and long-lasting polymer that is resistant to corrosion, chemicals, and weathering. Because of its minimal maintenance requirements, simplicity of installation, and long-term durability, vinyl sheet pile is becoming more and more common in construction projects. Vinyl sheet pile, unlike traditional materials such as wood, steel, or concrete, does not require frequent maintenance or coating, making them a more cost-effective alternative in the long run.

Vinyl sheet pile is also environmentally friendly because it is reusable and does not leak dangerous chemicals into the soil or water. Because of its lightweight qualities, it is simple to transport and install, necessitating minimal use of heavy machinery and labour. Overall, vinyl sheet pile is a versatile and cost-effective solution for a variety of construction and civil engineering projects. Its durability, low maintenance requirements, and environmental benefits make it an appealing choice for contractors and engineers.

An effective alternative to steel sheet piling for bulkheads, seawalls and cutoff walls. They are also superior to alternative materials like concrete and wood. The main advantage of vinyl sheet piles is the superior corrosion resistance when exposed to seawater, where no oxidation occurs.

Vinyl sheet piles are lightweight and resistant to corrosion and chemical damage. They are often used in projects where environmental impact is a concern.

Wooden sheet pile

A wooden sheet pile is a type of retaining system comprising timber planks or boards. We commonly employ them in construction and civil engineering projects with a requirement for a retaining wall, either temporary or permanent. Hardwood sheet piles are a more environmentally friendly and long-lasting alternative to steel or concrete sheet piles. and they are widely utilised in places where environmental impact is a concern. In excavation work, we utilise them for braced sheeting and temporary structures. It must have some sort of preservative treatment for its utilisation in permanent structures above the water table. Even after treatment with a preservative, a timber sheet pile has limited life. Timber sheet piles are bonded using tongue and groove connections.

Features of wooden piles

Timber piles are not suitable in strata that contain gravel and boulders. Hardwood sheet piles are ideal for shallow excavations and we frequently utilise them in building projects where noise and vibration are a concern. They are lightweight and easy to handle, making them a popular choice for jobs requiring speedy installation. In comparison to other retaining wall materials, wooden sheet piles are also more affordable. Yet, there are significant drawbacks to using hardwood sheet piles. They are not as robust as steel or concrete sheet piles and require frequent maintenance to prevent rot and insect infestation. They may also be prone to warping and deformation if exposed to dampness for a lengthy period of time.

Hardwood sheet piles may not be suited for usage in places with high water tables or salinity in the soil, as these variables might accelerate the decomposition of the timber. Overall, hardwood sheet piles are an efficient and environmentally friendly option for small-scale building projects and temporary retaining walls. Yet, their durability and susceptibility to deterioration and warping make them unsuitable for long-term or large-scale applications.

wooden sheet piling
Wooden sheet pile

Concrete sheet pile

Concrete sheet piles are retaining walls constructed from precast reinforced concrete sections. We frequently employ them in civil engineering and building projects with a requirement for long-term retaining structures.

We must handle and drive the piles carefully, and provide the necessary reinforcement. The most common application of Concrete sheet pile is in deep excavations where soil conditions are unfavourable and we require lateral support. They are impermeable and can withstand hydrostatic pressure, making them excellent for usage in places with high water tables. We provide a capping to the heads of the piles by casting a capping beam, while we cut the toes with an oblique face to make driving and interlocking easier. They are relatively heavy and thick, and while driving, they displace significant amounts of the earth.

The driving resistance rises as a result of the considerable volume displacement. Concrete sheet piles are also resistant to weathering, corrosion, and erosion, making them a durable solution under extreme conditions. Concrete sheet piles are available in a range of dimensions and we can interlock them to create a continuous wall. We can place them in a variety of ways, including driving, vibrating, and pushing. The method of installation depends on the accessibility to the site, the depth of the installation, the state of the soil etc.

concrete sheet piling

Concrete sheet piles are a strong and long-lasting alternative, but their installation may be more costly and time-consuming than that of other retaining wall materials. However, installing them requires large machinery, which can be difficult in places with restricted access or space. Overall, concrete sheet piles are a viable option for permanent retaining walls in deep excavations and severe soil conditions. They are a preferred option for projects involving coastal protection and flood control due to their strength and resistance to water and erosion.

Aluminium sheet piles

Aluminium sheet piles are lightweight, strong, and corrosion-resistant, making them an ideal choice for projects that require a lightweight and durable material.

Composite sheet piles

We manufacture Composite sheet piles from a combination of materials, such as steel and concrete, to provide additional strength and durability. They often find applications in projects that require high load-bearing capacity.

Cellular sheet pile

We usually design Cellular sheet pile with hollow sections that allow for increased strength and load-bearing capacity. They find application in projects that requires a high degree of lateral support.

Cold-formed sheet piles

Cold-formed sheet piles are made by bending steel sheets into a desired shape. They find application in projects requiring lower strength and load-bearing capacity.

Conclusion

Each type of sheet pile has its own advantages and disadvantages, and the choice of material and design will depend on the specific requirements of the project. Proper design and installation are essential to ensure the stability and safety of the sheet pile wall, and consultation with an experienced engineer is recommended before selecting a specific type of sheet pile for a project.

chemical engineering, Steam distillation

Steam Distillation – Process, Principle and Diagram – Full Details

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Steam distillation is a separation process in which we separate a mixture of immiscible components by introducing steam and subsequently condensing the vapours. In this blog, I will walk you through steam distillation and its principles. First, let us understand the instances in which we opt for Steam distillation over other separation processes.

  1. What is Steam Distillation?
  2. Steam Distillation Principle
  3. Steam Distillation Process
  4. Steam Distillation Advantages
  5. Conclusion

What is Steam Distillation?

In the typical distillation process, we usually have a mixture of components that are miscible with one another. The vapour pressure that the combination exerts on heating depends on the components that make up the mixture.

steam distillation diagram

To start boiling, the vapour pressure of the mixture should become equal to the atmospheric pressure or the pressure to which it is subjected to. Hence we must heat the system of the liquid mixture to a temperature where the system can create enough vapour to equalise the operating pressure or the atmospheric pressure.

The temperature that must be attained depends on the operating pressure; if it is less than one atmospheric pressure, the temperature that is to be attained is relatively lower; if it is greater than one atmospheric pressure, the temperature to be attained is relatively higher.

In some circumstances, it might not be possible to perform this. Some of those instances are as follows:

  • When separating materials with very high boiling points, we have to supply more heat to raise the temperature of the mixture. As a result, the procedure uses more energy and is more expensive.
  • If the mixture contains any thermally unstable components, raising the temperature too high could cause the components to decompose and have an impact on their qualities.
  • The process becomes energy-intensive if we have a binary combination in which one component boils at a high temperature while the other is non-volatile in nature.
  • We can easily handle these situations using the method of steam distillation.

Steam Distillation Principle

In the previous blog, we saw Raoult’s law which states that the partial pressure of each component in a miscible ideal mixture is equal to the product of its vapour pressure and mole fraction.

Pa = Xa * Pv

Steam distillation process

Hence it is clear that the liquid components can’t exert their actual vapour pressure but a corrected vapour pressure (or what we call the partial pressure) which is always less than its pure component vapour pressure ( since mole fraction is always less than 1 )

But, in the case of liquid mixtures in which the components are non-miscible, they can exert their entire vapour pressure as its partial pressure. That is, the total pressure becomes equal to the sum of the individual vapour pressures for immiscible liquid mixtures. Their combined vapour pressures can easily reach the external pressure before the vapour pressure of either of the individual components cross it. Hence the boiling point of the mixture would be lesser than the boiling point of either of the components.

Now, let us assume that water is one of the components in the immiscible mixture. Then we can bring that mixture to a boil at under 100 0C in one atmosphere ( Boiling Point of water at 1 ATM = 100 0C ) if we keep the pressure constant at 1 ATM. In other words, we can lower the operating pressure needed to boil the mixture by introducing steam.

The main concept behind steam distillation is that we use steam to help create the pressure needed to balance the operating pressure. We must be careful to only employ components that are immiscible with water while using steam.

Steam Distillation Process

Consider a binary mixture where component A is a high-boiling component and component B is a non-volatile component. Let’s say A is insoluble in water. We feed the mixture into the column. Using a steam coil, we raise the feed mixture’s temperature. A sparger forces the steam through another steam line. Steam enters the column through the feed mixture and adds to the vapour pressure. When it reaches the working pressure, it causes the creation of vapours of A at a significantly lower temperature. The non-volatile component is eliminated as residue but remains in the feed. Steam and Component A is routed via a condenser where they are easily separated after condensation.

Steam Distillation Advantages

We frequently use steam distillation since it has various advantages over other extraction methods. They are as follows:

  1. the process produces organic compounds devoid of solvents;
  2. Additional separation procedures are not necessary;
  3. It has a huge processing capacity on an industrial scale;
  4. Inexpensive equipment

Shall we wrap up?

Conclusion

In this blog, we saw the process of steam distillation, its advantages and its applications.

civil engineering

Unit weight of steel bars – How to calculate?

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Calculating the unit weight of steel bars with various diameters is crucial when creating a schedule for bar bending. The total weight of steel bars/TMT bars weight required for the project’s construction can be calculated once we know the unit weight of steel.

Steel is the most commonly used structural material. Steel’s basic components include metallic iron, non-metallic carbon, and minor amounts of nickel, silicon, manganese, chromium, and copper, among others. High tensile strength makes it a popular construction material for civil engineering projects. Steel reinforcement bars, often known as rebar, are placed in concrete members to enhance their tensile strength. As we all know, steel is utilised to construct structural members such as columns, beams, footings, foundations, and building slabs. Steel bars of various sizes are supplied by the manufacturer, with lengths of 12 metres or 40 feet.

  1. Why Unit Weight of steel bars Calculation is Important?
  2. How to calculate the steel bar weight/ TMT bars weight?
  3. Calculation of weight of steel bars per Running Meter
    1. Weight of steel per Meter
    2. Weight of steel per foot
    3. Weight of steel bars/TMT bars weight per meter

Why Unit Weight of steel bars Calculation is Important?

It is essential to comprehend the weight of steel bars since we estimate them as 100 metres 20 mm bar, 100 feet 16mm bar, and so on (is the sign for diameter). Steel bar manufacturers, on the other hand, will not interpret this notation and will measure the steel bars in weight. So we have to order them in kilogrammes, quintals, or tonnes. This article will go through how to use the steel weight formula to determine the steel bar’s weight.

How to calculate the steel bar weight/ TMT bars weight?

Steel bar unit weight is the weight of steel per unit volume. Its SI unit is kg/m3. The unit weight of steel is typically measured as follows

  • Kilogrammes per cubic metre (7850 kg/m3),
  • Kilo Newton per cubic metre (78.5 kN/m3),
  • Grams per cubic centimetre (7.85 g/cm3).
Unit weight of steel
Unit weight of steel bars

Calculation of weight of steel bars per Running Meter

Let’s start with a 12 mm diameter.

The length of the rod L = 1 meter.

Steel has a density of 7850 kg/m3.

Let us see how the formula calculates the weight of steel bars.

Area of steel rod (Circular shape) = πr2 or πD2/4

Hence the wt of steel bar formula

= Area of steel x Density of steel x Length of steel

Where

Area of steel = πD2/4

The density of steel = 7850 kg / m3

Length of steel = 1 mtr

Diameter of steel = D mm

Weight of steel per Meter

= πD2/4 x 7850 x 1m = 3.14 x (D2 / 4) x 7850 x 1m

In this equation,

the Diameter is in mm and the Density (Unit Weight) is in m3

Let us convert the Diameter in mm2 to m as below

1 mm = 1/1000 m , 1 mm2 = 1/(1000)2 mm2

= 3.14 x (D2 /4 ) X 1/(1000) 2 X 7850 X 1

Weight of steel bars formula= D2 x 6162.5 x 1/(1000)2

= D2 x 1/(0.006162)-1

= D2 / 162.28

For calculation purposes, we used to take D2/162

Weight of steel rod per Running meter = D2/162 where D is the diameter of steel rod in mm

For a 12 mm dia rod,

D = 12 mm

Weight per meter = 12 x 12 /162 = 0.889 kg per rmt or meter length or unit length

If you want to know the steel weight per foot. 1 metre = 3.281 ft. Just multiply the same.

Weight of steel per foot

1 metre = 3.281 ft. Just multiply the same.

= D2/162 x 3.281 = D2 / 533

Weight of steel bars/TMT bars weight per meter

Let us have an idea about the unit weight of common diameters of reinforcement steel used in civil engineering construction.

Weight of steel bars/TMT bars weight per meter
BUILDING CONSTRUCTION

Difference between Built up Area, Carpet area, Plinth Area

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You may run into terminology like “carpet area,” “built-up area,” and “super built-up area” if you’re considering purchasing a home. There are various types of areas in a building’s floor plan. Reading a floor plan is an important skill for a civil engineer to have. These are various methods of describing a property’s area. In this article, we will see about the different types of areas.

  1. Types of areas in Building Construction
    1. Real Estate Regulation and Development Act, 2016, (RERA)
    2. Plot area (Areas of building)
    3. Carpet area (Areas of building)
    4. Plinth area
    5. Super built-up area
    6. Set back area

Types of areas in Building Construction

We should be informed with the following building construction practises before making home buying plans. Following are the terminologies usually followed in dealing with building construction.

  • Plot area
  • Built-up area or Plinth area
  • Carpet area
  • Setback area
  • Super built-up area

Before getting into these terms first we have to know what is RERA 

Real Estate Regulation and Development Act, 2016, (RERA)

The Real Estate Regulation and Development Act, 2016, (RERA) is an act established by the Indian parliament. The main objective of RERA is to give prompt information between the buyers and sellers. This increases transparency and reduces the chance of cheating.

There are three different ways to calculate the area of the property. 

  • In terms of the Carpet area
  • In terms of Built-up area
  • In terms of Super built-up area

While buying a property buyer should pay for the area which is usable. RERA provides safety of money, buyer protection and balanced agreement.

Areas of Building
Areas of Building

Plot area (Areas of building)

The plot area includes the complete area which you own. This area comes under the fencing.

Plot area
Plot area

Carpet area (Areas of building)

Carpet area is a term which the real estate agent uses the most. It is the area of the building which can be covered by using carpet. It is also called a net usable floor area. 

Carpet Area = Total floor area – Area of internal/external walls

But as per RERA Carpet area = Total Floor area – Area of external walls

According to RERA flats should be sold on the basis of carpet area. The carpet area as per RERA is the area of usable spaces such as bedrooms, kitchen, bathroom, toilet etc. It also includes an area covered by internal partition walls. It excludes areas such as Balcony, utility areas, external walls area, open terrace area, lift, lobby, staircase etc. Mostly carpet area is 70% of its built-up area. 

Carpet area
Carpet area

Plinth area

The plinth area is also known as the Built-up area. It is the total area of the building within the plot area. It is mostly 30% of the total plot area. 

Built-up Area = carpet area + Area of walls

It includes living room, bedrooms, utility, bathroom, wall thickness, kitchen, balcony closed staircases etc. and excludes open terrace area, lift, open staircase, swimming pool etc. It is 10 to 15 % more than the carpet area.

Plinth area
Plinth area

Super built-up area

Super built-up area was used to measure the area of property before the RERA act came into existence. Because the super built-up area lowers the rate per square foot. Saleable area is another name of super built-up area.

Super Built-Up Area = Setback area+Built-up Area+20% of common area 

Super built-up area includes common areas like swimming pool, clubhouses, lobby, staircase, Lift, etc. and the built-up area of the flat. 

Set back area

Set back area is the space between the boundary and the building. It is the minimum open space necessary around the building. As per the municipal regulation a specific margin should be provided between building and road. 

Setback area = Built-up Area – Plot area

Setback area
Setback area

This provides sufficient ventilation, ease in vehicle movement and protection from other entities

architectural finishes, Doors

Types of doors – Top 7 door types explained

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Types of doors commonly used in residential, commercial, and industrial construction depend on the application area, durability required, the purpose of the door, etc.

What is a door?

A door is a movable barrier or mechanism for opening and closing an entranceway or a building/room. The purpose of the door in this urban environment is security and privacy. Apart from security, safety, and privacy, an aspect of art, beauty, and elegance is associated with it. The entrance door acts as a warm welcome to the areas inside.

This article is about the types of doors popularly used in civil construction.

  1. Classification of doors in Civil Engineering
    1. Types of doors in civil engineering– location based
      1. Exterior door
      2. Interior door
    2. Types of Doors – Based on Materials
      1. Wooden Door/Timber Door
        1. Demerits of wooden doors
      2. Glass Doors
      3. Metal Doors
      4. Types of Doors – Flush Doors
      5. PVC Doors
      6. Types of Doors – UPVC Doors
      7. Types of Door – Aluminium doors
  2. Conclusion

Classification of doors in Civil Engineering

Doors come in a number of types. The selection of a door type, on the other hand, is determined by the location, purpose, aesthetic needs, material availability, security, and privacy. Doors types are typically classified as follows.

  • Location based
  • Based on material
  • Based on operation mechanism

Types of doors in civil engineering– location based

The doors types are classified as follows

  • Exterior Doors
  • Interior Doors

Exterior door

An outside door is one that allows entry to a building/house. An outside door’s main function is to safeguard the building as well as the security and privacy of the occupants of the building. While selecting an exterior door, style, colours, finishes, and aesthetic looks to match the architectural theme must be considered.

Interior door

Interior doors provide access to interior spaces like bed, kitchen, special functional rooms, toilets, etc. However, choice of material and type depends on the nature of privacy, security, and purpose of the room. Interior doors used to be lighter than exterior doors.

Types of Doors – Based on Materials

The door choice is confirmed based on the material to be used. For that, we should have a better idea of the readily available, durable, and aesthetically matching materials. Following are the popular choices of doors based on materials used in construction nowadays.

  • Wooden Doors
  • Glass Door
  • Metal Door
  • Flush Door
  • PVC door
  • Aluminium Door
  • UPVC door

Wooden Door/Timber Door

Wooden doors types are the most common and premium choice for both external and internal doors. They are the preferred choice due to their classy and elegant looks, high durability, and ability to match any architecture theme. Moreover, they are aesthetically pleasing and are widely available on a reasonable budget. Wooden doors can be custom-made for any functional requirements and design. They are the oldest material used and never lose their sheen even after long years.

wooden door
wooden door
  • Easily available
  • Easy working
  • Best material for front doors due to its high durability.
  • Used for any functional requirement.
  • Wooden doors are mostly polished rather than painted for exposing the natural grain looks.
  • Simple and easy installation.
  • Carving works are easily done on wooden doors.
  • Wooden doors are soundproof, got high thermal insulation capabilities and are strong.
Demerits of wooden doors

Even though wooden doors are superior materials they have their demerits also. However, needs periodic maintenance to retain the sheen and looks.

  • Needs periodic maintenance to retain the sheen and looks.
  • Wooden doors on long exposure to moisture may deteriorate.
  • Prone to termite attacks.
  • May sags

Glass Doors

Glass doors are for areas where the availability of natural light and open feeling is the main functional requirement. They are mainly used in areas where privacy is not a prime factor-like back yard, balcony doors, cabin doors, etc.

Glass doors are elegant and give an enhanced look to the house. However, the main problem with glass doors is the safety and privacy factor and the possibility of glass breaking. The glass breaking problem is managed by using small glass pieces for front doors. The glass should be safety glass or toughened glass.

Metal Doors

Steel is one of the preferred and favorite alternatives to wood for both external and internal doors. Mild steel or Galvanized steel is used for the manufacturing of doors. These doors are manufactured in solid and hollow types and are a safer, durable, and stronger option when compared to wooden doors.

metal door
metal door

Steel door frames are usually combined with wooden, PVC, steel, and flush door shutters. Steel door frames are manufactured by pressing steel sheets, angles, channels, etc. Holdfasts and hinges are welded to the steel frames.
Steel frames are popular and are used for residences, factories, industrial buildings, etc. They are economical than conventional wooden frames.

Metal door shutters are manufactured from high-quality cold-rolled Mild Steel (MS) sheets, with a steel face and rock wool or foam insulation. Steel is a more economical and stronger option compared to other materials even though steel may not look as attractive as wooden or glass doors.
Metal doors are available in different tones and shades. They are durable, have minimal maintenance, and provide excellent security.

Types of Doors – Flush Doors

The flush door is made of a timber frame covered with plywood from both sides. However, the hollow core is filled with rectangular blocks of softwood just like block boards. Flush door surface finished with decorative finish by fixing veneers. The flush door is usually laminated or veneered to match the architectural themes. These doors are usually hinged type and have one side opening only. The frame can be of wooden, PVC, or steel.
Flush doors got a seamless look and are economical, look elegant, and are easily available in the market.

flush door
flush door

While providing these doors for toilets, baths; the inner face of the door should be covered with aluminum sheets to protect against water.

PVC Doors

PVC or polyvinyl chloride doors are a very popular choice for doors. They are available in a range of colors and styles. Furthermore these doors have high resilience, are anti-destructive, termite-proof, moisture-resistant, lightweight, etc. As a result they are best suited for areas with moisture chances like bathroom areas.
Polyvinyl doors come in a variety of designs types. colors, style and looks beautiful. Similarly these doors do not corrode like steel or disintegrate like wood and do not need much maintenance.
They are very simple and easy to install and are scratch-proof. These doors are not preferred for front doors due to their lightweight characters and inability to resist environmental conditions. These doors are cost-effective when compared to wooden and metal doors.

Types of Doors – UPVC Doors

uPVC stands for Unplasticised Polyvinyl Chloride. It is a form of plastic that is hard and inflexible, also known as rigid PVC. UPVC doors are a preferred choice of architects and home owners due to the superior qualities they offer when compared to other door materials like wood, metal , PVC etc

  • Easy to clean and maintain – UPVC doors can be cleaned by simply wiping with a soft cloth soaked with mild detergents even though they may not peel or cracks after years of usage.
  • UPVC Profiles are manufactured to accommodate double glass units (DGU) in fact provides excellent thermal and acoustic insulations. Furthermore glass panes can be substituted with reflective glass to reflect sunlight and keep the rooms cooler in summers.
  • Durability – UPVC is a highly durable material, in addition to that allows for the construction of doors and windows that are long-lasting. In addition to all above they are dust-proof, termite-proof, moisture, and weather-resistant.
  • Ease of installation – Similarly UPVC doors are very fast and easy to install.
UPVC doors
UPVC doors

Types of Door – Aluminium doors

Aluminium doors due to their excellent and durable qualities are the most preferred option for designers and architects. They are durable, strong and maintenance free material. The fabrication and installation is very easy and got the choice of using as member for DGU units for thermal insulation applications. Aluminium is expensive, however considering the superior qualities aluminium is preferred in most of the areas.

Conclusion

Apart from the types described above there are a lot of doors varieties available in the market to cater each and every situation and applications. However, these door type selection has to be in line with the requirements.

CONCRETE, quality tests on concrete

Ultrasonic pulse velocity test || UPV Test – Types and Methodology

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The ultrasonic pulse velocity test, or UPV test, is an example of a non-destructive concrete test. Generally, hardened concrete is subjected to non-destructive testing (NDT) and destructive tests (DT). Concrete is the world’s oldest and most significant construction material. Therefore, concrete testing is crucial for assessing the stability, strength, durability, and condition of structures.

Non-destructive testing of concrete is a way of analysing concrete structures without causing damage. This aids in ensuring the structural quality and condition. The strength of the concrete is also influenced by various characteristics, including hardness, density, curing circumstances, ingredient quality, workability and water-to-cement ratio, etc.

This article discusses the UPV test, which is one of the most well-liked and reliable non-destructive tests carried out on concrete structures.

  1. Ultra sonic Pulse Velocity test (UPV Test)
  2. Relevant IS code for Ultrasonic Pulse Velocity Test (UPV Test)
  3. Ultrasonic Pulse Velocity tester
  4. Principles of Ultrasonic Pulse Velocity test
  5. Objective of UPV tests
  6. Factors affecting Ultrasonic pulse velocity test
  7. Methodology of Ultrasonic Pulse velocity tests
    1. Direct method
    2. Indirect method
  8. Result interpretation of UPV testing
  9. Conclusion

Also read : Bitumen tests – 9 tests for flexible pavements

Ultra sonic Pulse Velocity test (UPV Test)

The most efficient and fast method of testing concrete is through ultrasonic pulse velocity tests, or UPV tests. The quality of concrete is assessed using the results of UPV tests, which evaluate the period of travel of ultrasonic pulse waves. A 50–55 kHz range must be maintained for the ultrasonic pulse wave’s frequency. The pulses are generated by the UPV tester’s pulse generator and are allowed to travel through the concrete. By monitoring the traversing distance and the duration, the pulse velocity can be determined. Higher velocity indicates that the density and elastic modulus of the concrete are higher.

Cracks and defects in the structure are detected using UPV tests. Significant variations in pulse velocity values are indicative of broken and degraded concrete. The concrete’s density and wave velocity are related. Therefore, this test has a tremendous potential for evaluating the quality of concrete.

Relevant IS code for Ultrasonic Pulse Velocity Test (UPV Test)

IS-13311 (Part 1):1992 (Reaffirmed- May 2013) “Non-Destructive Testing of Concrete- Methods of Test (Ultrasonic Pulse Velocity)”

Related posts from vincivilworld

Ultrasonic Pulse Velocity tester

The UPV tester is the name of the type of equipment used to measure ultrasonic pulse velocity. The following accessories are included in ultrasonic pulse velocity tester.

  • Electrical Pulse generator
  • Pair of Transducers (probes)
  • Amplifier
  • Electronic timing device
Ultrasonic Pulse Velocity Tester
Ultrasonic Pulse Velocity Tester

Principles of Ultrasonic Pulse Velocity test

The electrical pulse generator generates pulses that are sent through the UPV tester’s transducer. Through the concrete surfaces, the pulse generates many reflections. Using the formula shown below, the pulse velocity is calculated.

Pulse velocity, V = L/T

where L is the traverse distance, T is the time for the receiver to receive the pulse

The geometry of the material is unrelated to the UPV test. Better concrete strength is associated with higher velocity and vice versa. One of the dynamic tests for concrete is the ultrasonic pulse velocity test.

Objective of UPV tests

The main objectives of the ultrasonic pulse velocity test or UPV tests are

  • To learn the homogeneity of the concrete.
  • Determines the presence of cracks, voids and imperfections. 
  • To calculate the elastic modulus of concrete. 
  • Finds the quality of concrete relative to the standard requirements. 
  • To determine the age of concrete. 

Factors affecting Ultrasonic pulse velocity test

The UPV test detects cracks and assists in structure development. However, a number of factors influence how pulse velocity is measured. As a result, compressive strength cannot generally be approximated from the pulse velocity. The following are the elements that impact the UPV test.

  • Presence of reinforcement
  • Water content
  • Mix proportion
  • Temperature of concrete
  • Concrete age
  • Stress level of concrete

Methodology of Ultrasonic Pulse velocity tests

Piezoelectric and magneto strictive types of transducers are suitable for use with the UPV test. Additionally, its frequency range should be between 20 and 150 kHz. The electronic timing device monitors time with an accuracy of 0.1 microseconds.

The transducer transmits the waves that travel through the concrete surface. The receiver transducer detects the electric signals that are generated once the pulse waves are transformed to them. The traversal length will be displayed as ( L). The electronic timing device calculates how long it takes for signals to arrive. Time is shown as (T).


The Electronic timing device measures the receiving time of the signals. The time is denoted as (T).

Pulse velocity (v) = L/T

There are three common methods for doing UPV tests. They are direct method and indirect method.

  • Direct Method of UPV Testing
  • Indirect Method of UPV Testing
Methodology of UPV test
Methodology of UPV test

Direct method

The maximum energy is transmitted at right angles to the face of the transmitter. As a result, to achieve the greatest results, the receiving transducer must be placed on the side of the transmitting transducer. This is referred to as the direct approach or cross probing.

Ultrasonic pulse velocity test
Ultrasonic Pulse velocity test -Types

Indirect method

In some circumstances, the opposite side of the structure may be inaccessible. The receiving and transmitting transducers are installed on the same face of the concrete members in this scenario. This is known as the indirect method or surface probing. This approach is less effective than the direct approach. The test findings are mostly influenced by the surface concrete, which has different properties from the structural components’ core concrete.

Result interpretation of UPV testing

The density and elastic modulus of concrete are correlated with the ultrasonic pulse velocity. This in turn depends on the components, mixing processes, placement techniques, concrete compaction and curing, casting temperature, etc.

The main causes of internal cracks and pockets in concrete are lack of compaction and concrete segregation. Lower pulse velocity values are a result of these concrete defects. However, the laboratory tests might have confirmed a well-designed concrete.

The range of pulse velocity in the direct method is as shown below.

  1. Above 4.5 Excellent
  2. 3.5 to 4.5 Good
  3. 3.0 to 3.5 Medium
  4. Below 3.0 Doubtful

Conclusion

The final assessment of compressive strength from UPV is not the sole criterion used to determine concrete strength. The strength is confirmed by comparing it to a compressive strength estimate derived from the same ingredient mix and conditions. The results of the UPV test and site tests conducted using similar ingredients may be correlated. When compared to actual UPV intensities, the numbers may change by about 20%.

Bitumen, Building materials

Bitumen types for road Layers – Bitumen Emulsion types

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Bitumen types for road layers are a vital topic to comprehend when it comes to road construction. Bitumen is preferred for flexible pavements in road construction because it has many advantages over other pavement construction materials. This article will demonstrate the importance of bitumen in road construction and the types of bitumen for road construction. Furthermore, bitumen emulsion types for road layers, different bituminous materials, cutback bitumen, bitumen grade, and bitumen attributes will be highlighted in this article.

  1. Bitumen types for Road layers /Flexible pavements 
    1. Tack Coat – Bitumen types for road layers
    2. Binder Course – Bitumen types for road layers
    3. Prime Coat – Bitumen types for road layers
    4. Base Course
    5. Sub Base Course
    6. Sub Grade
  2. Protective Asphalt
    1. Seal coat
    2. Slurry Seal
    3. Chip Seal
    4. Micro Surfacing
    5. Fog Seal

Bitumen types for Road layers /Flexible pavements 

The   flexible  pavement  structure   consists  of  the  following  layers: 

  • Tack   Coat  
  • Binder   Course 
  • Prime  Coat  
  • Base   Course  
  • Subbase Course
  • Subgrade Course
Bitumen types for road layers

Keep in mind that the primary component of the road is not protective asphalt. Protective asphalt is deployed to safeguard the road’s surface. Every layer mentioned above uses a different type of bitumen. We will illustrate what types of bitumen are used in each of these layers.

Tack Coat – Bitumen types for road layers

The application of coatings is a critical phase in the construction of asphalt roadways. Generally, a tack coat is a thin layer of asphalt emulsion or liquid bitumen used in between layers of hot mix asphalt to prevent slippage. Mostly, MC30 cutback bitumen, CRS-1, and CRS-2 emulsion bitumen are utilised in a tack coat layer of bitumen. The lower layer is sealed by the presence of a tack coat, which also increases the strength of both asphalt layers.

Bitumen types for road Layers

MC-30 is a medium-curing cutback bitumen that is ideal for cold climates. Basically, asphalt emulsions are the most often used tack coat materials. However, the most widely used slow-setting emulsions are SS-1, SS-1h, CSS-1, and CSS-1h (1). The usage of rapid-setting asphalt emulsions like RS-1, RS-2, CRS-1, and CRS-2 for tack coats is also on the rise.

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Binder Course – Bitumen types for road layers

The base course and the surface course are separated by the binder course. Generally, a binder course is used to keep the road surface from moving. Because the binder course is made out of coarse aggregates, less bitumen is utilised in the manufacture of this asphalt. In the hot asphalt of the binder course, various grades of pure bitumen can be utilised. The various grades of pure bitumen used in binder courses are listed in the table below.

Penetration Grade Viscosity Grade
30/40VG 10
40/50VG 20
60/70VG 30
80/100VG 40 
120/150
Bitumen types for road layers

Prime Coat – Bitumen types for road layers

A prime coat is a coating that is applied directly to the base layer. The primary objective of utilising the prime coat is to improve the bond between the base layer and the asphalt mix layer. It also fills in the voids. A priming coat might aid in sealing the base layer. The bitumen in prime coatings is either CSS or CMS.

Prime coats aid in reducing dust while protecting the granular base’s integrity throughout construction. In the event of a foundation that will be covered with a thin hot mix layer or a chip seal for a low-volume roadway, priming enables a good bond between the seal and the underlying surface, which might otherwise delaminate.

A primary coat is primarily responsible for safeguarding the substrate of a construction project before applying additional layers. They can also function as a binder with secondary and tertiary compounds in the preparation of asphalt, improving the adherence of the layers. Following the prime coat, a tack coat is applied to provide an adhesive bond between the tack coat and the subsequent layer of coating. For asphalt prime coat systems, the tack coat is one of the most vital parts of the process, as it connects the subsequent layers and forms the base of those layers’ strength.

Base Course

The base course is placed directly on top of the subbase course. This layer has a higher permeability than the sub-base layer because it is composed primarily of coarse aggregates. Basically, the base course, which is the first layer in direct contact with traffic, moves the weights from the upper layers to the sub-base course. Different base courses used in pavement include sand or stone base, macadam base, and bitumen base.

road-layers-of-flexible-pavement
road-layers-of-flexible-pavement

Sub Base Course

The first layer of flexible pavement constructed on the ground is the sub-base course. This layer is typically composed of river sand, an alluvial cone, and broken rock. Bitumen and cement can be used to stabilise the sub-base soil.

Sub Grade

It is the surface upon which further pavement layers such as the sub-base course, base course, and asphalt layers are placed. The subgrade absorbs any load tension or weight that is transferred from the top levels. A good subgrade should be able to support weights for a considerable amount of time without deforming.

Protective Asphalt

Generally, Protective asphalts are used to seal the road surface and improve the asphalt temporarily. However, It should be noted that asphalt sealing can cause the asphalt to become more slippery. Pure bitumen with low humidity and soluble bitumen are both utilised in protective asphalt. Because of its quickness and ease of installation, protective asphalt is more cost-effective than hot asphalt. There are various varieties of protective asphalts, some of which are listed below:

  • Seal coat
  • Slurry seal
  • Chip seal
  • Micro-surfacing
  • Fog seal

Seal coat

A seal coat is used to provide a long-lasting surface texture and to keep the surface waterproof. However, this kind of protective asphalt can be made using a variety of emulsion bitumen types, including CSS-1, SS-1h, SS-l, and CSS-1h.

Bitumen types for road layers

Slurry Seal

Generally, a slurry seal is used to lessen the harm done by bitumen oxidation. In the slurry seal, emulsion bitumens SS-1, SS-h1, CSS-1h, and CQS-1h are used. A slurry seal is appropriate for pavements with little to moderate damage, such as narrow cracks. However, it is not appropriate for severe damage such as holes.

Chip Seal

A chip seal is a thin protective surface that is applied to a pavement or subgrade. Water cannot easily seep through the base layer due to the chip seal. This layer also prevents freezing in areas where the temperature is below zero. Adding this layer improves the road’s reflectiveness for nighttime driving. A rapid-setting emulsion containing a CRS-2, RS-2, HFRS-2, and PMB is the best type of bitumen for chip sealing.

Micro Surfacing

Micro-surfacing aids in the sealing of cracks and the protection of existing bituminous layers against surface voids and minor ruts. Among the benefits of adopting this layer are environmental compatibility, cost-effectiveness, and fast construction time. PMB bitumens such as PMCQS-1h, PMQS-1h, and CQS-1P are suited for it.

Fog Seal

A fog seal is intended to neutralise the oxidation process that occurs over time. This layer protects the pavement surface by leaving a hard layer. This layer employs emulsion bitumen such as SS-1, SS-1h, CSS-1, or CSS-1h.

Roads, TRANSPORTATION ENGINEERING

Bitumen for roads – Bitumen Uses, Grades and Types

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Bitumen for roads is an important topic to understand when it comes to road construction. Bitumen is used in road construction because of the wide range of features and advantages it possesses over other pavement construction materials. The significance of bitumen in the construction of roads will be demonstrated in this article. In addition, we shall see bitumen road layers, various bituminous materials, cutback bitumen, bitumen grade, and bitumen properties.

  1. Bitumen for roads – Bituminous binder types
    1. Bitumen vs Tar – Comparison
    2. Tar manufacturing
  2. Desirable properties of bitumen- an important topic in bitumen for roads
  3. Bitumen for roads – Types of Bituminous materials
    1. Cutback bitumen
    2. Bituminous emulsion
  4. Grade of bitumen for roads – Types and Uses
  5. Bitumen road layers

Bitumen for roads – Bituminous binder types

There are two types of bituminous binder for road construction.

  • Bitumen (by distillation of crude oil)
  • Tar (Produced from coal)

So, what are the difference between them?

Bitumen vs Tar – Comparison

The table below shows a comparison between tar and bitumen.

BitumenTar
Petrolium productDistillation of coal or wood
Soluble in carbon disulphide and carbon tetrachlorideSoluble in toluene only
Temperature succeptibility is lowTemperature succeptibility is higher than bitumen
Free carbon content is lessFree carbon content is more
Comparison between tar and bitumen

Now, let’s sneak into the manufacturing of tar, being one of the important bituminous materials

Related posts from vincivilworld

Tar manufacturing

Bitumen for roads - Construction in progress
Bitumen for roads – Construction in progress

Generally, tar is made by heating coal inside a chemical apparatus. Most tar is produced from coal as a byproduct of coke production, but it can also be produced from petroleum, peat or wood.

The major steps in tar manufacturing are,

  • Coal undergoes carbonation and produces crude tar
  • Crude tar undergoes distillation/ refining and produces a residue
  • The residue blends with distilled oil fraction and produces tar

I am going to tell more about the properties of bitumen now.

Also read: Classification of roads-5 types of roads full details

Desirable properties of bitumen- an important topic in bitumen for roads

Bitumen for roads - Properties
Bitumen for roads – Properties

The desirable properties of bitumen are,

  1. Viscosity of bitumen during mixing and compaction is adequate
  2. Bituminous material should not highly temperature and susceptible
  3. In presence of water the bitumen should not strip off from aggregate
  4. The adhesive property of bitumen binds together all the components without bringing about any positive or negative changes in their properties
  5. Bitumen is insoluble in water and can serve as an effective sealant
  6. Due to versatility property of Bitumen it is relatively easy to use it in many applications because of its thermoplastic property
  7. Bitumen play a vital role in distributing the traffic loads on the pavement to the layers beneath

Bitumen for roads – Types of Bituminous materials

Okay. So, what are the types of bituminous materials that are used in flexible pavement construction? Below is the list for you.

  1. Paving grade material
  2. Modified bituminous binder
  3. Cutback bitumen
  4. Bitumen emulsion

Among the list, cutback bitumen is the major. Let me tell you more details about cutback bitumen.

Cutback bitumen

Cutback bitumen is the bitumen the viscosity of which is reduced by a volatile diluent. It is used in low-temperature mixing.

Three types of cutback bitumen are available

  1. Rapid curing
  2. Medium curing
  3. Slow curing

The diluent while mixing varies with the type of cutback bitumen.

Type of cutback bitumenDiluent
Rapid curingNafthal, gasoline
Medium curingCarosine or diesel oil
Slow curingHigh boiling point gas oil
Type of cutback bitumen and suitable diluent

Bituminous emulsion

bitumen emulsion
Bitumen emulsion

A bitumen emulsion is a liquid product in which a substantial amount of bitumen suspended in a  finely divided condition in an aqueous medium and stabilized by means of one or more suitable material

Three types of bitumen emulsions are available

  1. Rapid setting
  2. Medium setting
  3. Slow setting

Also read: Alignment of road: Factors affecting- obligatory points with figures

Grade of bitumen for roads – Types and Uses

To determine the grade of bitumen, penetration test is conducted. The results are expressed in 1/10 mm. When penetration value is represented as 80/1000, it is called grading of bitumen.

The old method of grading is viscosity test. Two viscosities kinematic and absolute and penetration value by penetration test results are collected. Based on this, bitumen is graded. The tables shows the grade of bitumen and values of viscosity in accordance with penetration.

Grade of bitumenAbsolute viscosityKinematic viscosityPenetration
VG 1080025080- 100
VG 20100030060- 80
VG 30240035050- 70
VG 40320040040- 60
Grade of bitumen and viscosity

Let me tell you the application of each of the grade of bitumen now.

VG- 10- Used in spray application since viscosity is very less

VG- 20- Used in cold area

VG- 30- Commonly used in India

VG- 40- High grade bitumen used in high traffic areas

Okay. So, lets’ learn about the bituminous layers.

Bitumen road layers

Let’s first look into the road layers to understand bitumen road layers.

bitumen road layers
bitumen road layers

The bitumen road layers come in the surface layer shown in the figure above. The figure below shows that. Bituminous mix consists of aggregate and binder. Aggregate consists of coarse aggregate, fine aggregate and filler less than 0.075mm.

Bitumen road layers
Bitumen road layers
  • Bituminous concrete consists of aggregate and bitumen.
  • Thickness of base course depends on grading of aggregate
  • Dense graded aggregates are provided in base course. That is the permeability will be very less
  • Number of voids should be very less
  • Dense bituminous macadam should be given as a binder course

So, the trip is over. Hope the time you spend for reading about the bitumen for road was worth it.

MUST READ: Road margins- 6 types of road margin in highway

Happy learning!

ACP sheets, architectural finishes

Aluminium Composite Panel || ACP sheets design

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Aluminium composite panel, also known as an ACP sheet, is a modern panelling material used for building exteriors (facades), interiors, kitchen cabinets, and signage applications.

Aluminium composite panels are flat panels having a non-aluminium core sandwiched between two thin coil-coated aluminium sheets. Aluminium Composite Panel is the most durable and flexible decorative surface material available, with enhanced performance attributes. This article discusses the production process, ACP sheet types, advantages, and applications.

  1. What is an Aluminium Composite panel or ACP sheets ?
  2. Types of Aluminium Composite Panels (ACP)
    1. Non fire rated Aluminium Composite Panel (ACP)
  3. Fire rated Aluminium Composite Panels
  4. Advantages of Aluminium Composite Panels
    1. Light weight
    2. Flexible
    3. Availability and colour choices
    4. Environmental friendly
    5. Dimensional stability
    6. Smooth and elegant
    7. Cost
    8. Weather resistant and Durable
  5. Applications of Aluminium Composite Panels
    1. External and internal architectural cladding/partitions
    2. Internal partitions
    3. Signage
    4. Interior work
  6. Conclusion

What is an Aluminium Composite panel or ACP sheets ?

Aluminum composite panels are made up of two thin layers of aluminium sheets sandwiched by a polymer core. ACP sheet’s polymer core is made of Low-Density Polyethylene (LDPE) or Polyurethane. These polymer cores are made of components that are flammable and not fire-resistant. Because aluminium has a low melting point, the Aluminium composite panel is more flammable when the combustible polymer core is present. The presence of a combustible polymer core limits the use of Aluminium composite panel in fire-prone areas.

To improve fire resistance, polymer cores should be specially treated or over 90% (Non-Combustible Mineral Fiber FR core) sandwiched between two layers of aluminium skins should be used. To preserve the ACP sheets, polyvinylidene fluoride (PVDF), fluoropolymer resin (FEVE), polyester coating, and other materials are applied. The typical thicknesses of aluminium composite panel are 2 mm, 3 mm, 4 mm, and 6 mm.

Aluminium Composite Panels
Aluminium Composite Panels – Façade

Types of Aluminium Composite Panels (ACP)

Depending on the usage and fire rating standards ACP sheets are classified into two categories

  • Non fire rated grade
  • Fire rated grade

Non fire rated Aluminium Composite Panel (ACP)

Two thin layers of aluminium sheets plus a sandwiched polymer core make up aluminium composite panels. Aluminium Composite Panel’s polymer core is made of polyurethane or low-density polyethylene (LDPE). These Aluminium Composite Panels are not fire-rated since they are flammable and could catch fire. The use of these sheets is restricted based on the fire rating. The image below depicts a typical cross-section of an ACP sheet that is not fire-rated.

Non Fire rated or Standard Aluminium Composite Panel - Typical section
Non Fire rated or Standard Aluminium Composite Panel – Typical section

Fire rated Aluminium Composite Panels

Depending on the core composition, fire-rated Aluminium Composite panel can withstand fire for up to 2 hours. The core materials are the fundamental distinction between ACP sheets that are fire-rated and those that are standard. While the fire-rated ACP has a specially formulated fire-resistant mineral core, the standard ACP uses LDPE/HDPE as its core material. Fire resistant mineral core uses Magnesium hydroxide as core for enhanced fire retardant qualities. As the name suggests, Fire Grade Aluminium Composite Panels have the unique capability to withstand extreme temperatures. The highest grade ACP is fire retardant ACP (A2 GRADE), which contains over 90% inorganic material content.

Aluminium Composite Panel - Fire retardant grade
Aluminium Composite Panel – Fire retardant grade (Credits – Alstrong )

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Advantages of Aluminium Composite Panels

Aluminium Composite Panels are widely used nowadays because of their countless unique properties. Let’s highlight a few of its unique features that set it apart from other panelling materials.

Light weight

When compared to other building materials like steel, Aluminium Composite Panel is lightweight. This significantly reduces the design loads on the structure with big spans and vast areas involved. Lifting and erecting ACP sheets is simple. This, in turn, minimises labour and construction costs while maintaining the schedule.

Flexible

The ACP sheet is flexible and very simple to use. The installation process is quick and simple, and the fixing framework construction is uncomplicated.

Availability and colour choices

This composite panel has exceptional flexibility because to the vast range of finishes it supports. Aluminium composite board can be textured, solid, mirror, or wood type to meet any architectural concept. The colour and feel of real stone and wood are effectively replicated on aluminium.

Environmental friendly

ACP is an environmentally friendly material that is composed of 85% recycled aluminium. ACP’s cover sheets and core material are both recyclable.

Dimensional stability

Aluminium composite panels got high dimensional stability and the material can remain stable for a long period without changing the dimensions.

Smooth and elegant

The exteriors of buildings can have a pleasant and attractive appearance because to the smooth, elegant ACP surface.

Cost

ACP sheet is the most economical panelling option when compared with other panelling materials. The cost depends on the core materials. The fire grade materials are costlier than standard non fire rated ACP.

Weather resistant and Durable

ACP panels are UV resistant and chemical resistant. They are unbreakable stain-resistant, weather-resistant, termite resistant, moisture resistant, and anti-fungal.

Applications of Aluminium Composite Panels

ACP sheet is mainly used for a wide range of applications due to its extraordinary qualities. Major uses of the ACP sheet are as follows.

  • External and internal architectural cladding 
  • Internal partition
  • False ceilings
  • Signage
  • Machine coverings
  • Container construction

External and internal architectural cladding/partitions

For exterior cladding/façade applications, ACP sheets are used, thanks to their versatile qualities like UV resistance, fire resistance, and durability. ACP sheets come in a wide range of colours to match any architectural style. ACP sheet is the material of choice for facades and partitions because of its lightweight characteristics, simple fixing procedures, and quick construction.

Internal partitions

Aluminium Composite Panels in combination with aluminium, UPVC etc are used for office cabins and internal partitions. Partitions can be done with minimal space wastage.

Signage

ACP is used to render a wide variety of flexible exterior signs, as signage and hoardings are being used for exterior applications and must survive changes in temperature or weather

Interior work

ACP sheets are used for interior applications such as wall coverings, false ceilings, cupboards, portable kitchen cabinets, tabletops, column covers, and more.

Conclusion

ACP sheets are Green and environmentally friendly, easy to clean, and can shorten the construction period. ACP panels are resistant to corrosion, prevents acid and alkali, and other types of corrosion. Due to these versatile properties, ACP sheets are one of the popular choices in the construction sector.

Formwork

Formwork in construction – Top 5 Formwork types

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Formwork in construction refers to a mould used to shape concrete into structural shapes (beams, columns, slabs, shells) for buildings and other structures. Concrete is one of the most popular building materials due to its exceptional properties and advantages. However, in order to create construction components, concrete must be poured into a specific mould. In order to achieve the desired shape precisely, concrete is occasionally poured into formwork, a type of temporary mould. Formwork types in construction can also be categorised based on the type of structural member they are used in, such as slab formwork for use in slabs, beam formwork for use in beams and columns, and so forth. The formwork and any accompanying falsework must be sturdy enough to support the weight of the wet concrete without experiencing significant distortion.

Timber formwork is the most prevalent type of formwork used for minor buildings. This article explores the various forms of formwork used in construction as well as their characteristics.

  1. Significance of formwork in construction
  2. Quality of good formwork in construction
    1. Easy removal
    2. Economy
    3. Rigidity and strength
    4. Less Leakage
    5. Supports
  3. De-shuttering Period as per IS 456 – 2000 for formwork in construction
  4. Advantages of formwork in construction
  5. Types of formwork in construction
    1. Timber formwork in construction
    2. Plywood formwork
    3. Metal formwork
      1. Advantages of metal/steel formwork
    4. Aluminium formwork
      1. Advantages of Aluminium Formwork:
      2. Disadvantages of Aluminium Formwork
    5. Plastic formwork

Significance of formwork in construction

Formwork is frequently used in a range of shapes and sizes in building, roads, bridges, tunnels, corridor linings, hydroelectric power dams, agriculture headwork, sewage pipeline works, and other applications based on our design materials in the form of PCC and RCC. Falsework is the term for the structures that are needed for formwork in order to prevent movement during construction procedures. Formwork in construction requires a qualified crew and appropriate supervision to ensure high quality. Poor accuracy and expertise during the creation of the formwork lead to subpar work, which wastes time and money.

Form work in construction
Formwork

25 to 30 per cent of the total price of concrete construction is made up of the cost of the formwork. For bridges, this cost proportion could be higher. However, depending on the complexity of the structure, this may exceed 60%.

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Quality of good formwork in construction

Although there are numerous formwork materials, the following are general performance characteristics to satisfy the objectives of concrete construction is as follows.

  • Easy removal
  • Economy
  • Rigidity and strength
  • Less leakage
  • Supports

Easy removal

The design of the formwork should be such that it may be quickly removed with minimal pounding, resulting in less damage to the concrete.

Economy

Formwork serves no purpose in ensuring the stability of completed concrete. So, keeping safety in mind, its cost might be reduced. The formwork should be constructed with reasonably priced, lightweight, readily available materials that are both recyclable and reusable.

Rigidity and strength

Good formwork should be capable to withstand any form of live or dead load. Formwork must be properly aligned to the target line, and levels must have a plane and solid surface. When exposed to weather, the formwork’s material shouldn’t swell or warp. When choosing the formwork, take into account the temperature of the pour as well as the type of concrete being used because both affect the pressure that is applied. Furthermore, the formwork must be sturdy enough to bear the weight of both wet and dry concrete.

Less Leakage

Joints must not leak at any point.

Supports

Formwork needs falsework, which consists of stabilisers and poles, in order to stop moving while construction is being done. Formwork needs to be supported by sturdy, rigid, and rigid supports.

De-shuttering Period as per IS 456 – 2000 for formwork in construction

Let us have a look into the de-shuttering period of various structural components as per IS 456-2000

Sr. No.Type of FormworkMinimum Period Before Striking Formwork
1.Vertical formwork to columns, walls, beams16-24 hours
2.Slab ( props left under )3 days
3.Beam soffits ( props left under )7 days
4.Props for Slab
(a).Spanning up to 4.5m7days
(b).Spanning over 4.5m14days
5.Props to Beam and Arches
(a).Spanning up to 6m14days
(b).Spanning over 6m21days

De-shuttering period as per IS 456

Advantages of formwork in construction

Formwork is unquestionably necessary for all construction projects; its fundamental benefit is that no other technique can take its place.

  • Concrete structures can be swiftly and affordably built by using formwork.
  • A formwork provides suitable access and working platforms throughout the whole construction process, thereby, enhancing worker scaffold safety.
  • Formwork helps to reduce project timelines and costs by shortening the floor-to-floor building cycle time, which implies that more projects can meet their budgetary requirements. This, in turn, enables construction managers to provide precise on-time shuttering and de-shuttering of formwork resources, which improves project effectiveness and resource utilisation.
  • Formwork assists in creating a smooth concrete finish surface.

Types of formwork in construction

The following are the major types of formworks commonly used in construction.

Timber formwork in construction

One of the first types of formwork utilised in the construction industry was timber formwork. Basically, timber formwork is the most versatile form, is built on-site, and has numerous advantages. In comparison to metallic formwork, they are incredibly lightweight and easy to install and remove. Timber formwork is versatile and can be built to any shape, size, or height. However, for minor projects where the use of local wood is permitted, these kinds of formworks are cost-effective. Prior to usage, the lumber must, however, undergo a thorough inspection to make sure it is termite-free. Timber formwork also has two disadvantages that should be considered: it has a short lifespan and takes a long time on large projects. Timber formwork is frequently recommended when labour costs are low or when flexible formwork is required for complex concrete components.

Timber formwork
Timber formwork in construction

The timber formwork should be well-seasoned, small in size, easy to nail without breaking, and free of slack knots. During shuttering, every face of timber that will make contact with the exposed concrete work must be even and smooth.

Plywood formwork

Generally, for plywood shuttering, sheets of waterproof, boiling-level plywood that are suited for shuttering are commonly used. These plywood sheets are attached to wooden frames to form the desired-size panels. Typically, plywood formwork is used in the sheathing, decking, and form-lining applications. Hence, Plywood formwork is the modern-day alternative to wooden formwork in construction. To support the concrete work, this formwork incorporates plywood. Plywood formwork results in a smooth concrete surface, which eliminates the need for concrete refinishing. Accordingly, with the use of large-size panels, a wider area can be covered. Basically, for jobs like fixing and disassembling, this might result in labour savings. The number of reuses is higher as compared to wooden shuttering. The number of reuses might be approximated to be between 10 and 15 times.

Plywood formwork
Plywood formwork in construction

Many of the same characteristics of timber formwork, such as strength, durability, and lightweight, also apply to plywood formwork. The ability of plywood shuttering to withstand moderate weather conditions is one of its key benefits. The surface of plywood seems to be sturdy, and it is robust enough to support the weight of concrete.

Metal formwork

Steel shuttering is composed of panels with thin steel plates that are connected at the edges by small steel angles. Suitable clamps or bolts and nuts can be used to secure the panel units together, Likewise, this type of formwork is used in the majority of bridge construction projects. Because of their long lifespan and adaptability, steel hardware and formwork are becoming more popular. Despite its potential cost, steel shuttering is beneficial for a wide range of applications and constructions. Basically, steel shuttering gives the concrete surface an extremely flat and smooth finish. It is ideally suited for circular or curved structures such as tanks, columns, chimneys, sewers, tunnels, and retaining walls.

Metal formwork
metal formwork

Advantages of metal/steel formwork

  • It gives the surface of the member a highly smooth and levelled finish.
  • Steel shuttering has a long lifespan and is effective and strong.
  • The honeycombing effect is reduced and it is waterproof.
  • It can be used more than 100 times.
  • The concrete surface does not collect moisture through the steel shuttering. Likewise, it is simple to assemble and de-shuttering.

Aluminium formwork

Aluminium shuttering resembles steel shuttering. The main difference is that aluminium has a lower density than steel, which makes formwork lighter. There are a few things to consider before using aluminium in a construction project. Compared to steel, aluminium is less strong. Aluminium shuttering is cost-efficient when deployed in several construction projects engineered for repeated use. The major disadvantage is that once the shuttering is constructed, it cannot be changed.

Aluminium shuttering

Advantages of Aluminium Formwork:

  • A smoother, cleaner surface finish is produced.
  • Generally, Up to 250 re-uses were intended for aluminium formwork.
  • It’s also cost-effective if numerous symmetrical structures need to be constructed.

Disadvantages of Aluminium Formwork

  • The initial cost is higher since aluminium formwork is now more expensive. Such formwork is cost-effective when used in symmetrical building designs.
  • Setting up initially takes some time.
  • Professional services are necessary in order to align and maintain this kind of formwork.
  • In order to prevent future leaks, the formwork holes made by wall ties should be correctly blocked.

Plastic formwork

Interlocking panels or modular systems, which are both light and strong, are used to construct plastic shutters. Generally, small, repeatable initiatives like low-cost housing complexes are where it works best.

Plastic formwork
Picture courtesy: Newstrail.com

Basically, plastic formwork is appropriate for plain concrete structures. Due to its lightweight and water-cleanability, plastic shuttering is ideal for large segments and multiple reuses. Its primary drawback is that it is less flexible than timber because many of its components are prefabricated. However, large housing projects and structures with similar shapes are increasingly using these shuttering techniques.

 

INDUSTRIAL NEWS, NEWS

UltraTech Cement commissions 1.9 mtpa cement capacity in Pali – Rajasthan

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On Tuesday, the Aditya Birla Group company announced that the 1.9 mtpa greenfield clinker-backed grinding capacity at Pali Cement Works in Rajasthan had been put into operation.

According to the corporation, this is a part of the first phase of capacity increase that was announced in December 2020.

With 5 different plant locations, the firm and its subsidiary can now produce 16.25 mtpa of cement in Rajasthan.

The total capacity of UltraTech Cement for the production of cement in India is currently 121.35 mtpa. Outside of China, UltraTech Cement is the third-largest cement manufacturer in the world, with a combined Grey Cement capacity of 121.25 MTPA.

Despite a rise in net sales of 15.78% to Rs 13,596, the cement manufacturer’s consolidated net profit fell 42.47% to Rs 756 crore.

bricks, BUILDING CONSTRUCTION

Types of bonds in brick masonry walls – Advantages and features

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Types of bonds in brick masonry commonly used in construction are detailed in this article. The process of bonding bricks with mortar in between them is known as brick masonry. Bricks are arranged in a pattern to maintain their aesthetic appearance and strength. This article is about the various types of bonds in brick masonry walls.

Bricks are rectangular construction materials. Bricks are commonly used in the construction of walls, paving, and other structures. They are also inexpensive and simple to work with.

  1. Types of Brick masonry bonds – Features
  2. Types of Bonds in brick masonry
    1. Stretcher bond – Types of Bonds in brick masonry
      1. Limitations of Stretcher bonds
      2. Applications of stretcher bonds
    2. Header bond – Type of Bonds in brick masonry
    3. English Bond – Types of bonds in brick masonry
    4. Flemish Bond
    5. Double flemish bond
    6. Single Flemish Bond
    7. Raking bond
    8. Zigzag Bond
    9. Facing Brick Bonds
    10. Dutch Bond
    11. Rat trap bond

Types of Brick masonry bonds – Features

For all types of brick masonry bonds to be stable and of high quality, the following characteristics must be followed.

  • Bricks should be uniform in size.
  • The lap should be a minimum of 1/4 brick along the length of the wall and 1/2 brick across the thickness of the wall.
  • Uniform lapping is to be maintained.
  • Avoid using too many brickbats.
  • For getting a uniform lap Length of the brick should be twice its width plus one joint.
  • The centre line of the header and stretcher in the alternate courses should coincide with each other for the stable wall.
  • Stretchers should be used in facing and a header should be used in hearing.

Types of Bonds in brick masonry

There are different types of brick masonry bonds. They are

  • Stretcher Bond
  • Header Bond
  • English Bond
  • Flemish Bond
  • Raking bond
  • Zigzag Bond
  • Herring-Bone Bond
  • Facing Bond
  • Dutch Bond
  • Diagonal Bond
  • Rattrap bond

Let us have a look at the most commonly used types of bonds in brick masonry.

Stretcher bond – Types of Bonds in brick masonry

The stretcher is the brick’s lengthwise face or otherwise known as the brick’s longer, narrower face, as shown in the elevation below. Bricks are laid so that only their stretchers are visible, and they overlap halfway with the courses of bricks above and below. Accordingly, In this type of brick bond, we lay the bricks parallel to the longitudinal direction of the wall. In other words, bricks are laid as stretchers in this manner. It is also referred to as a walking bond or a running bond. Additionally, it is among the simplest and easiest brick bonds.

Stretcher Bond - Types of bonds in brick masonry
Stretcher-Bond

Limitations of Stretcher bonds

  • Stretcher bonds with adjacent bricks, but they cannot be used to effectively bond with them in full-width thick brick walls.
  • They are only suitable for one-half brick-thick walls, such as the construction of a half-brick-thick partition wall.
  • Stretcher bond walls are not stable enough to stand alone over longer spans and heights.
  • Stretcher bonds require supporting structures such as brick masonry columns at regular intervals.

Applications of stretcher bonds

Stretcher bonds are commonly used as the outer facing in steel or reinforced concrete-framed structures. These are also used as the outer facing of cavity walls. Other common applications for such walls include boundary walls and garden walls

Header bond – Type of Bonds in brick masonry

Generally for header bond, the header is the brick’s widthwise face. In brick masonry, a header bond is a type of bond in which bricks are laid as headers on the faces. It’s also referred to as the Heading bond. The header is the brick’s shorter square face, measuring 9cm x 9cm. As a result, no skilled labour is required for the header bond’s construction. While stretcher bond is used for half brick thickness walls, header bond is used for full brick thickness walls that measure 18cm. Generally, in the case of header bonds, the overlap is kept equal to half the width of the brick. To achieve this, three-quarter brickbats are used in alternate courses as quoins.

header bond - Types of bonds in brick masonry
header bond

English Bond – Types of bonds in brick masonry

English bond uses alternative courses of stretcher and headers and is the most commonly used and the strongest bond in brick masonry. However, a quoin closer is used at the beginning and end of a wall after the first header to break the continuity of vertical joints. Mostly, a quoin close is a brick that has been cut lengthwise into two halves and is used at corners in brick walls. Similarly, each alternate header is centrally supported over a stretcher.

Types of bonds in brick masonry - English bond

Flemish Bond

In Flemish bond, each course is a combination of header and stretcher. Accordingly, the header is supported centrally over the stretcher below it. Generally,closers are placed in alternate courses next to the quoin header to break vertical joints in successive layers. Flemish bond, also known as Dutch bond, is made by laying alternate headers and stretchers in a single course. The thickness of Flemish bond is minimum one full brick.The drawback of using Flemish bond is that it requires more skill to properly lay because all vertical mortar joints must be aligned vertically for best results. Closers are placed in alternate courses next to the quoin header to break vertical joints in successive There are two types of Flemish bond

  • Double Flemish bond
  • Single Flemish bond

Double flemish bond

The double flemish bond has the same appearance on both the front and back faces. As a result, this feature gives a better appearance than the English bond for all wall thicknesses.

Single Flemish Bond

The English bond serves as the backing for a single flemish bond, which also includes a double flemish bond on its facing. As a result, both the English and Flemish bonds’ strengths are utilised by the bond. Similarly ,this bond can be used to build walls up to one and a half brick thick. Howerver,high-quality, expensive bricks are used for the double-flemish bond facing. Cheap bricks in turn may be used for backing and hearting.

The appearance of the Flemish bond is good compared to the English bond.  Hencer, flemish bond can be used for a more aesthetically pleasing appearance. However, If the walls must be plastered, English bond is the best choice.

Flemish bond

Raking bond

Raking bond is a type of brick bond in which the bricks are laid at angles. In this case, bricks are placed at an inclination to the direction of walls. Generally, it is commonly applicable for thick walls. Normally laid between two stretcher courses. There are two types of Raking bonds

raking bond
  • Diagonal bonds
  • Herringbone bonds

Diagonal bonds

In diagonal bonds, bricks are laid inclined, the angle of inclination should be in such a way that there is a minimum breaking of bricks. These dioganal bonds are mostly applicable for walls of two to four brick thickness. Similarly, the triangular-shaped bricks are used at the corners. 

Herringbone bonds

This type of bond is applicable in thick walls. The bricks are laid at an angle of 45 degrees from the centre in two directions. Mostly used in paving. 

Zigzag Bond

In this type of bond, bricks are laid in a zig-zag manner. It is similar to the herringbone bond. Since Zig zag bond has an aesthetic appearance it is used in ornamental panels in brick flooring. 

zig zag bond
zig zag bond

Facing Brick Bonds

In facing bond bricks are used of different thicknesses. It has an alternative course of stretcher and header. The load distribution is not uniform in this type of bonding. So it is not suitable for the construction of masonry walls.

facing bond
facing bond

Dutch Bond

It is a type of English bond. The specific pattern of laying bricks for building a wall is known as English and Dutch bonds. The primary distinction is that English Bond is a bond used in brickwork that consists of alternate courses of stretchers and headers. Dutch bond – made by alternating headers and stretchers in a single course.

Rat trap bond

rat trap bond
rat trap bond

Another name of the rat trap bond is the Chinese bond. In this type of bond, the bricks are placed in such a way that a void is formed between them. These voids act as thermal insulators. Thus provides good thermal efficiency. It also reduces the number of bricks and the amount of mortar. Construction of rat trap bonds requires skilled labours.

CONCRETE

Concrete Mixing || Mixing concrete – Objectives and types

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Concrete Mixing or Mixing of concrete is the complete blending of the ingredients necessary for the production of a homogeneous concrete. In the previous blogs, we saw different types of concrete and their quality tests. Today, let me walk you through the details of it.

To begin with, let’s try to understand the objectives of mixing concrete and concrete mixing types

  1. Objectives of Concrete Mixing
  2. Concrete Mixing Types
    1. Hand Mixing of concrete
      1. Process – Hand Mixing of concrete
    2. Machine Mixing of Concrete
      1. Concrete Mixing Machine
      2. Machine Mixing Process
    3. Ready Mix Concrete
    4. Mixing Ratios
  3. Conclusion

Objectives of Concrete Mixing

How many of you have wondered why we mix concrete? Read on to find the answers.

  • To manufacture high-quality fresh concrete, proper mixing of materials is critical. 
  • The surface of all aggregate particles is coated with cement paste during the mixing phase.
  • For the desired workability and performance of concrete in both the fresh and hardened states.
  • To avoid segregation and bleeding.

In the next section, we will learn the types of concrete mixing

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Concrete Mixing Types

There are three methods to produce efficient and high-quality concrete.

  • Hand Mixing – Mixing concrete manually without a mixer machine.
  • Machine Mixing – Mixing using a mixer machine.
  • Ready Mix Concrete – Mixing is done in an automatic or semi-automatic batch plant.

Let’s dig deeper into each of them.

Hand Mixing of concrete

  • Method of manually mixing the concrete materials without the use of a mixer machine. 
  • Hand mixing is done only for small jobs where the concrete demand is low and quality control is not critical. 
  • Uniformity of mixing is difficult to achieve by hand mixing. It necessitates extra caution and effort. 
  • In the case of hand mixing, 10% more cement should be applied to the nominal mix concrete proportion.
Hand mixing of concrete
Hand mixing of concrete

Process – Hand Mixing of concrete

  • Hand mixing is done on a flat iron sheet plate base that is hard, clean, and non-porous.
  • On the platform, a measured amount of sand is placed.
  • Then the cement is poured over the sand.
  • In a dry state, the sand and cement are thoroughly combined with shovels several times until the mixture achieves an even colour.
  • The coarse aggregates are then spread out on top of the above mixture and thoroughly mixed. 
  • The whole mixture is properly mixed by twisting it from centre to side, back to centre, and then to the sides several times.
  • After that, depression is rendered in the mixed materials’ nucleus.
  • 75 per cent of the necessary amount of water is then poured into the depression and mixed with shovels.
  • Finally, the remaining water is applied, and the mixing process is repeated until the concrete has a uniform colour and consistency. 

The total time for concrete mixing does not exceed 3 minutes.

Let’s move on to the next method ie mechanised concrete mixing.

Machine Mixing of Concrete

  • The method of combining concrete materials with a concrete mixer system is known as machine mixing. 
  • It meets the demands of fast mixing times, optimal consistency, and homogeneous concrete efficiency. 
  • Since it ensures uniform homogeneity, machine mixing of concrete is best suited for large projects requiring large quantities. 

Concrete Mixing Machine

It is also known as a concrete mixer is a machine that mixes cement, aggregate (such as sand or gravel), and water in a uniform manner to shape concrete. A rotating drum is used to combine the components in a traditional concrete mixer. Concrete mixers powered by gasoline, diesel, or electricity are now widely available. The mixer machine is mostly used for mixing ingredients by volume. They are also used for mixing ingredients by weight by providing weigh batcher.

Mixer machine in action
Mixer machine in action

Machine Mixing Process

  • Wet the inner surfaces of the concrete mixer drum first.
  • The coarse aggregates are added first, followed by sand, and finally cement, in the mixer.
  • In a mixing machine, combine the products in a dry state. In most cases, 1.5 to 3 minutes should suffice.
  • While the machine is running, slowly add the appropriate amount of water after the dry materials have been thoroughly mixed. 
  • Don’t use any extra water.
  • Concrete must be mixed in the drum for at least two minutes after adding water.

We have seen the details of machine mixing. How about getting an idea about ready-mix concrete?

Ready Mix Concrete

  • Ready Mix Concrete (RMC) is a specialised material in which the cement, aggregates, and other materials are weighed and batched at a central location, then mixed either in a central mixer or in truck mixers. Then it is shipped to construction sites.
  • The consistency of the resulting concrete is much superior to that of site-mixed concrete.
  • Useful on congested sites or in road construction where space for a mixing plant or aggregate storage is limited or nonexistent. 
  • Quality control of concrete is simple in this process.

So far, I have showed you the types of concrete mixing and its procedures. Now its time to throw some light on concrete mixing ratios.

Ready Mix concrete plant
Ready Mix concrete plant

Mixing Ratios

The proportions of concrete components such as cement, sand, aggregates, and water are known as concrete mix ratios. The method of building and mix designs are used to determine these ratios. In comparison to other mixing processes, the water/cement ratio in RMC can be easily managed.

Conclusion

To summarise,

  • Hand blending of concrete is the cheapest method.
  • It is only recommended for very limited projects requiring a small amount of concrete since consistent concrete consistency is difficult to achieve with this method. 
  • It ensures proper material mixing.
  • When compared to site mixing (both hand and machine mixing), RMC takes less time and produces a higher quality product.
  • It’s also very handy when you need a large amount of concrete per day.
Building materials, CEMENT

Test of cement on site – Field tests of Cement

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Test of cement on site or field tests of cement is one of the most crucial things to be performed to assure the quality of the construction. Every structure is made up of hundreds of different building materials, such as sand, cement, aggregates, bricks, tiles, marble, and so on. However, the quality of the building materials is crucial for producing a high-quality structure and should be regularly evaluated at various phases of construction. Cement is the most important material used in construction and is responsible for the overall strength of the structure. In order to guarantee excellence in building, cement quality must be properly.

This article is about the various test of cement on-site or field tests of cement to ensure quality.

  1. Test of cement on site – Significance
  2. How to check cement quality?
  3. Test of cement on site / Field tests of cement
    1. Checking the manufacturing date of cement
    2. Visual checking for Lumps for the test of cement on site.
    3. Feel test of cement on site
    4. Heat of cement
    5. Colour
    6. Water float test
    7. Setting test
    8. Conclusion

Test of cement on site – Significance

Cement plants are generally found in isolated areas near limestone mines. Generally, clinker is produced by cement companies at a centralised clinkerization plant. Clinkers are either ground at the clinkerization facility or transported to strategically placed grinding units for grinding and cement bag packing. The manufactured and packed cement is transported and delivered to the prescribed destinations by road or rail. Even with the finest protection, the cement still has the potential of absorbing moisture while being transported. After absorbing moisture, the cement tends to harden, deteriorating its quality. Because of these unforeseen concerns, cement must be tested for quality before being used in construction. Basically, cement testing is carried out in accredited laboratories.

How to check cement quality?

The characteristics of cement are often determined by laboratory tests. Lab tests need time, specialised equipment, and expertise to evaluate and interpret the data. All of the cement’s qualities might not be able to be tested on-site. To address this issue, cement tests are divided into two types.

  • Field Tests of Cement

This article is about the field tests of cement.

test of cement on site
FIELD TEST OF CEMENT

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Test of cement on site / Field tests of cement

Some simple field tests can be used to confirm the quality of cement. Generally, these tests do not require the use of costly equipment or professional skills, and the results are obtained quickly. We can determine whether to accept or reject the cement by doing these quick tests, analysing the findings, and drawing conclusions about its quality. These are preliminary evaluations, and the cement’s quality is confirmed by factors such as how smooth it feels to the touch and its colour etc.

  • Checking the manufacturing date of cement
  • Visual checking for lumps
  • Feel test of cement
  • The heat of cement test
  • Colour test of cement
  • Water float tests
  • Setting tests
Test of cement on site
Field tests of cement

Checking the manufacturing date of cement

When stored under perfect conditions, the cement must be utilised within 90 days of manufacture. The manufacturing date and batch number are imprinted on each cement bag. By verifying the manufacturing date, we can get a good indication of how old the cement is and decide whether to use it. In addition, every batch of cement is accompanied by a Manufacturers Test Certificate, which can be requested and examined to verify the dates of manufacture.

Visual checking for Lumps for the test of cement on site.

Cement can be inspected for visible lumps. To establish the potential existence of lumps, you can press the cement bag’s corners. This test determines if the cement has hardened or not.

Feel test of cement on site

Feel a pinch of cement between the figures. Cement has to feel smooth and not grainy. By this test, we can rule out the presence of any adulterated material like sand mixed with cement.

Heat of cement

Put your hand inside a bag of cement that is open. If the cement is of good quality and has not yet begun to hydrate, the hand feels cool.

Colour

Cement is usually greenish-grey in colour. We can verify and confirm the colour of the cement on-site. However, the type and source of the ingredients can affect the colour of the cement.

Water float test

This test is performed to find out whether there are impurities in cement. A cement hand is thrown into a bucket of water. The cement floats for a while before settling down if it is good cement free of impurities or other foreign objects. Impurities in the water can cause the cement to settle instantly.

Setting test

A thick paste of cement is applied to a glass piece and slowly immersed in water for 24 hours. The cement piece won’t break or alter shape while it sets and maintains its original shape. This cement is regarded as excellent.

Conclusion

We have the opportunity to contact cement manufacturers through their customer services if we have any questions about the product’s quality and they will be happy to help. It is possible to confirm field observations with laboratory tests. Cement quality should never be compromised during construction. Because the most crucial component that affects the durability and quality of a structure is cement.

ALSO READ : WHAT ARE THE PROPERTIES OF CEMENT?

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Cofferdams, dams

Cofferdams-Types of Cofferdam and construction

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Cofferdams are enclosures built inside bodies of water such as lakes and rivers to provide a dry working environment throughout the construction period. Cofferdams are temporary dykes that are built across a body of water. They allow the water to be pumped outside, ensuring a clean and dry construction site.

This article is about the significance and definition of Cofferdam and about the different types of cofferdams preferred in construction works.

  1. Significance of cofferdams
  2. What is a Cofferdam?
  3. Types of cofferdams
    1. Earthen cofferdam
    2. Rock-fill cofferdams
    3. Single walled cofferdams
    4. Double walled cofferdams

Significance of cofferdams

Construction in water is the most challenging task in civil engineering. A safe and dry working environment is necessary to preserve the project’s safety and construction quality. However, various strategies are used to construct structures in the water and maintain the area’s dryness. One of the most popular and widely utilised ways is the use of cofferdam.

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What is a Cofferdam?

Making cofferdam involves building watertight barriers all around the construction site, pumping the water out to expose the water, and then erecting the cofferdams. For bridge piers, marine jetties, ports, etc. cofferdams are preferred. Size, water depth, water flow velocity, and other factors affect the design and types of cofferdam. Let us have a look into the types of cofferdams popularly used in construction.

Types of cofferdams

Depending on the design requirements, water depth, soil conditions, type of material used, etc., coffer dams are classified into many types.

  • Earth cofferdam
  • Rock fill cofferdam
  • Single sheet pile cofferdam
  • Double-wall sheet piling cofferdam
  • Braced cofferdam
  • Cellular cofferdam

Earthen cofferdam

Earthen cofferdam is the most common and simplest type of cofferdam. They are appropriate for locations with minimal water depth and water current. Sand, soil, clay, and boulders that are readily available locally are used to construct earthen cofferdam. The earthen cofferdam must be at least one metre above the maximum water level.

When an area of excavation is quite extensive, earthen cofferdam is used and require a sizable base area. To withstand water pressure and seepage, impervious clay core or sheet piles are driven in the centre. In order to prevent scouring and possible dam failures, the upstream side is stone-pitched. These technologies do not, however, completely provide waterproof zones. Generally, to remove the water, pumps and waterproofing systems must be installed.

Earthen Cofferdams
Earthen Cofferdams

Rock-fill cofferdams

When compared to earthen cofferdams, rockfill cofferdams are superior. The choice of rockfill dams is influenced by the cost and availability of rocks in the area. Generally, the rockfill dam’s maximum height should be limited to under 10 feet. The rockfill area is pervious and will be lined with an impervious clay layer to prevent seepage and dam failure.

Rock filled Cofferdams
Rock filled cofferdam

Single walled cofferdams

When the depth of the water is less than 6 metres and the area of work is localised, such as on a bridge pier, single-walled cofferdams are preferred. Basically, single-walled coffer dams are primarily built by driving steel sheets into the inside as a support layer after driving timber sheets into the exterior as guide piles. In situations where the water is deep, guide piles may be steel sections.

After the guide piles have been driven, wales or runners made of wood logs are bolted to the guide piles at appropriate vertical intervals. Wales are used to position the inside sheets’ distance from the wooden planks at a specific distance as shown in the figure. Mostly, these wales are fastened to the sheets using bolts from both sides.

Single walled Cofferdams
Single walled cofferdam

The inside sheet piles have strong bracing. Sandbags are positioned on both sides of the walls to increase stability even more. For clay, the penetration depth should be approximately 1 metre, 0.5-0.75 metres for sand, and 0.25-0.5 metres for gravel, etc. Construction can begin when the interior water has been pumped out.

Also Read : Reservoirs vs Dams – Reservoir – types and functions

Double walled cofferdams

Double-walled cofferdams are preferred when the construction area is large, the water depth is higher than 6 metres, and single-walled cofferdams appear to be uneconomical. Double-walled cofferdams Consist of two straight, parallel vertical walls of sheet piling coupled together, with the space between them filled with soil. If the height is greater than 3 mtr, double wall sheet piles must be strutted as illustrated in the figure.

Double walled cofferdams
Double walled cofferdams

In order to give stability to the cofferdam, the filling materials must be carefully chosen while taking the coefficient of friction into account. The sheet piles are driven into the bed in the upstream area to a good depth to avoid leaking from the ground below.

CONCRETE, waffle slab

Waffle Slab or Ribbed slab details and Construction, Advantages

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Waffle slabs are ribbed reinforced concrete slabs. A waffle slab often referred to as a ribbed slab, is a structural component that is plain on top and has a grid pattern on the bottom. A waffle slab also called a two-way joist slab got ribs running perpendicular to each other in two directions on the underside. This slab resembles pockets of waffles because of its grid pattern. Hence they are named Waffle slab systems.

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For spans longer than 40 feet (12 metres), waffle slabs are chosen because they are stronger than flat slabs, flat slabs with drop panels, two-way slabs, one-way slabs, and one-way joist slabs. These are more expensive than other slabs but in turn, are more rigid and stable. Waffle slabs are apt for both ceiling and floor slabs. Slabs are one of the important structural components of a building. They provide a flat surface and help in transferring load. This article is about what is waffle slabs, the Construction process, Advantages and Disadvantages. 

  1. What is a waffle slab – Details and construction
  2. Waffle slab construction details
    1. In situ construction
    2. Precast
    3. Prefabricated
  3. Advantages of Waffle slab 
  4. Disadvantages of Waffle slab

What is a waffle slab – Details and construction

A waffle slab is a type of slab that is appropriate for industrial and commercial buildings. Waffle slabs are also referred to as two-way joist slabs or ribbed slabs. They have a flat top and grids on the underside. It has greater strength than flat slabs and hence is suited for longer spans. It enables both distributed and point vertical actions. The bottom layer of concrete reinforcement in waffle slabs is replaced by concrete ribs running in two orthogonal directions. Additionally, the rib depth should range from 135mm to 235mm. Because the overall depth of the floor increases as the depth of the ribs does. The structure’s lateral loading is impacted by this.

Waffle slab - supports and pods

Waffle slab construction details

The waffle slabs need only 70% of concrete and 80% of steel from the concrete and steel used for the construction of the raft slab. The construction stages of the waffle slab include the following

  • The first step is to create the forms
  • Place the formwork components in place.
  • Position your waffle pods or moulds on the shuttering. Generally, the pods are typically constructed of plastic, and they come in a variety of sizes and shapes. The size of the pod is determined by the requirements and span length. A significant number of pods are necessary for greater spans. Accordingly, the same size pods should be used for the entire slab.
waffle pods and beam supports
  • Place the support components horizontally and vertically according to the connectors.
  • Lay out the waffle pods and spacer within the formwork in a grid pattern beginning at one corner, following the instructions in the design.
waffle slab grid supports
Waffle slab supports
  • Fix the pod corners to the framework using cube joints.
  • Position reinforcement bars on the spacers between the waffle Pods.
  • Reinforcement is added in the two directions after the formwork has been fixed.
  • Lay the top mesh out according to the design specifications, then secure it where necessary.
  • Making sure connecting ribs are filled, pour the concrete and give it a good vibrating.
  • After the setting of the concrete, remove the frames into which the waffles are embedded. Then slowly remove the waffle forms. 

The construction of a waffle slab can be done in three ways

In situ construction

This process entails placing formwork and pouring concrete over it. A slab is cast on-site in the desired size and according to the design.

Waffle slab
waffle slab (https://styrofoamindustries.com.au/

Precast

Using this technique, the casting of the slab panel is done elsewhere, and it is then placed, connected, and reinforced with concrete.

Prefabricated

In this procedure, reinforcement is built into the slab panels using prefabricated steel bars. Slabs are manufactured elsewhere and brought to the location to be erected.

Advantages of Waffle slab 

  • It is suitable for large-span structures and can be achieved with less concrete and rebar than similar conventional slabs
  • They require only a fewer number of columns.
  • It possesses a higher load-carrying capacity
  • It has higher structural stability
  • They have a good aesthetic appearance. 
  • Waffle slabs are suitable for roof slabs and floor slabs.
  • Waffle slabs have high vibration control capacity
  • The construction of this slab can be done faster and easier.
  • They are light weighted 
  • They require low construction costs, Hence they are economical when compared to other conventional slabs of the same span
  • It requires only less amount concrete and can be reinforced with mesh or rebars.

Disadvantages of Waffle slab

  • Requires Expensive formwork
  • Requires skilled workmen and supervision for the construction of waffle slabs. 
  • Higher maintenance cost
  • The increase in the depth of ribs leads to an increase in the floor height.
  • This type of slab is not suitable for windy and slope areas.
CONCRETE, curing

Curing of Concrete – Concrete Curing Methods explained

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Curing concrete is the process of preserving the requisite moisture and temperature in hardened concrete for continued hydration. Concrete’s curing is crucial for sustaining the material’s longevity and design strength. This article discusses the importance of curing and the various concrete curing methods prevailing on construction sites.

  1. Curing of concrete methods
  2. Why Curing of concrete is important?
  3. Concrete Curing time as per IS 456-2000
  4. Concrete curing methods
    1. Water Curing method
    2. Membrane Curing method
    3. Steam curing method
  5. Conclusion

Curing of concrete methods

Curing is the process of retaining moisture to allow fresh concrete to reach its intended strength in a predetermined manner through a hydration reaction. Concrete is a mixture of cement, aggregates, and water in fixed designed proportions calculated based on specific strength requirements. The water to cement ratio is the most important factor in these proportions (Water cement ratio). In order to facilitate the hydration reaction, the water-cement ratio must be maintained. If the water evaporates quickly, there will not be enough water available for the hydration process. Because of this curing of concrete is required.

Curing assists in the retention of moisture until the hydration process is complete and it reaches the required strength. The American Concrete Institute (ACI) Committee 301 recommends a minimum cure duration equal to 70% of the required compressive strength. According to IS 456-2000 standards and construction norms, the curing period of 7 days/10 days is the time required to achieve at least 70% of the intended compressive strength. That is why concrete is cured for 7-10 days.

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Why Curing of concrete is important?

Perfect curing is necessary for the following reasons in order to achieve good strength and serviceability:

  • Curing prevents concrete from drying and maintains the acceptable temperature range by preventing moisture loss.
  • Curing increases the strength and decreases the permeability of hardened concrete.
  • Curing prevents the formation of cracks caused by thermal and plastic shrinkage.
  • Concrete curing maintains a strong link between the components and the reinforcement.
  • Curing can provide the desired strength and a durable concrete free of cracks.
  • Concrete curing assists in achieving high serviceability performance by improving abrasion resistance.

Also Read : Concrete Pumps Types – Application and advantages

Concrete Curing time as per IS 456-2000

According to the Indian Standard IS 456 – 2000, concrete should be allowed to cure for a minimum of seven days while using ordinary Portland cement and for a minimum of ten days while using blended cement or concrete with mineral admixtures. Additionally, it suggests that the curing time should not be less than 10 days for structures exposed to hot, dry weather and 14 days in case for or blended cement or cement with mineral admixtures.

OPC cement = 7 Days (Normal conditions) and 14 Days ( Hot and dry weather)

Concrete with mineral admixture or blended cement (PPC cement) = 7 Days (Normal conditions) and 14 Days ( Hot and dry weather)

Concrete curing methods

The curing method and time primarily depend on structure type, site conditions, and ingredient parameters. Some of the curing methods adopted in constructions sites are as follows.

  • Water curing
  • Membrane Curing
  • Steam curing

Water Curing method

Water curing is the most popular and common method adopted in construction sites. Basically, this method maintains or retains water on the concrete surface by various methods. This includes ponding, sprinkling and fogging, and saturated wet coverings or left-in-place forms.
Similarly, these methods prevent water loss from the concrete surface by continuous wetting of the exposed surface of the concrete.

Water curing
Water curing

Membrane Curing method

The basic concept of membrane curing is reducing the loss of water from the surface of the concrete. Generally, membrane curing methods uses curing compounds or impervious plastic sheets. Curing compounds are available in water-based and acrylic-based types. They form an impermeable membrane and reduces the loss of moisture.

Membrane curing /Curing compound
Membrane curing /Curing compound

Steam curing method

The steam curing process accelerates the process of strength gaining by using heat and providing additional moisture. Generally, this speeds up the early hardening process. Basically, these methods are familiar in prefabricated structures and factory-made precast components for the speedy recovery of form works.
Accordingly, Steam curing keeps the surface moist and raises the concrete temperature to speed up the strength achievement rate.

Steam curing - Precast factory
Precast factory

Conclusion

Now a days curing activity is not taken seriously and this hampers the strength and quality. Likewise, this is an activity to be done with utmost care to ensure design strength and serviceability of structures.

Intelligent transportation system, TRANSPORTATION ENGINEERING

Intelligent transportation system – Components of Intelligent transportation system

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Intelligent transportation system is a hot topic among all civil engineering subjects that has gained popularity and many countries are successfully implementing it. With the rapidly exploding population, ITS has even become a mandatory technique in all countries. Here, we are going to read through the main components of the intelligent transportation system. We will swim through the benefits of intelligent transportation system in the middle, then to uses and challenges of ITS.

  1. What is intelligent transportation system?
  2. Components of intelligent transportation system
  3. Benefits of intelligent transportation system
  4. Uses and challenges of intelligent transportation system
    1. 1. Use of cameras equipped with automatic number plate recognition(ANPR)
      1. Advantages
      2. Challenges
    2. 2. Speed violation recording cameras
      1.  Advantage
      2. Challenges
    3. 3. Cameras for recording violations of passing through red-lights at intersections
      1. Advantages
      2. Challenges
    4. 4. Equipping the transportation system with GPS
      1. Advantages
      2. Challenges
    5. 5. Use of intelligent routing systems for public transportation passengers
      1. Advantages
    6. 6.  Modern informative systems for offenders
      1. Advantages
      2. Challenges

What is intelligent transportation system?

What is Intelligent Transport System is the first step to dive in the topic. They are advanced applications which, aim to provide innovative services relating to different modes of transport and traffic management and enable various users to be better informed and make safer, more coordinated, and ‘smarter’ use of transport networks. In ITS the information and communication technologies are applied in the field of road transport, including infrastructure, vehicles and users, and in traffic management and mobility management, as well as for interfaces with other modes of transport.

Another answer to the question of what is Intelligent transportation system (ITS) is that, it is the application of sensing, analysis, control and communications technologies to ground transportation in order to improve safety, mobility and efficiency. ITS includes a wide range of applications that process and share information to ease congestion, improve traffic management, minimize environmental impact and increase the benefits of transportation to commercial users and the public in general.

Now, let me walk you through the main components of intelligent transportation system.

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Components of intelligent transportation system

Components of intelligent transportation systems

The main components of intelligent transportation system are,

1. Accurate tracking system
GPS enabled vehicles along with smartphone apps will help citizens to track buses and other vehicles.

2. Electronic timetables
Schedules of bus service should be updated in standard format which can be easily read by people and utilised by softwares.

3. Smart model to predict time of arrival
Transportation studies like that be conducted in IIT Madras, funded by Ministry of Urban Development. should be encouraged to obtain a robust algorithm to predict the arrival time of buses, which is what a citizen needs.

4. Standardisation by regulating authority

This is very important among all the components of intelligent transportation system. An authority should be set up which can standardise various components of the public transport and encourage the use of better and smart IT services in transport sector

5.Smart commuting

Latest information on traffic jams, accidents and ways for navigation

6. Mobile technology

App based technology, incentives for young technical entrepreneurs

7. Smart traffic control

Dynamic controls of traffic signals instead of current static control, automated system.

8. Scalability

The ITS should be easily applicable to 2nd tier cities so that problem of congestion doesn’t arise in the first place

9. Improved and better BRT system enacted with public participation

10. Installing CCTVs on traffic routes and in buses.

11. Creation of flyover and overbridges to eliminate need of traffic lights

12. Electronic payment of fare

13 Traveller’s advisory system like the use of advisory radio, SMS services, internet etc

14. Highway Management Systems: Use ramp metering techniques to measure and regulate by knowing the traffic entering or leaving the highway

15. Emergency Management Systems: To manage any unforeseen emergencies

16. Railroad Crossing: Gives signals about approaching rail junctions

17 Wireless communication System

18. Safe driving Support System

This includes,

a) Right turn collision prevention system

b) vehicle detection system
c) Pedestrian detection system

d) voice guidance

e) display warning

18. Electronic toll payment System

19. Computational technologie

20. Inductive loop detection and sensing technology

21.Freeway management.

Cool! Now how are these components of the intelligent transportation system benefiting transportation? Let’s see below.

Benefits of intelligent transportation system

traffic at night - Components of intelligent transportation systems

The main benefits of intelligent transportation are as follows.

  • Develop (and subsequently renew), a secure and effective revenue collection system – this has formed the backbone of the ITS
  • Develop enhanced operations management capabilities to provide reliable services and deal with disruptions
  • Provide communications for staff security
  • Provide improved passenger information
  • Obtain data for planning, resource optimisation and performance monitoring
  • To assist the achievement of the quantity and quality of the service required in the service contract with the province of Florence

• To generate the trip logs, analysis and reporting required by the province of Florence under the service contract

• To manage the daily operations, on both normal and disrupted state

• To manage the driver vehicle handovers and shift-changes

• To provide the platform for real-time and other information to passengers

• To provide the platform for e-ticketing

• To identify vehicle faults and assist rapid response

• To support demand responsive transport and other non-standard mobility services

• To generate and manage data for post-event analysis, including running time analysis, scheduling, resource optimization, and incident investigation

So, I walked you through the important benefits of intelligent transportation system.

Its time to see the results now.

Uses and challenges of intelligent transportation system

Components of intelligent transportation systems

1. Use of cameras equipped with automatic number plate recognition(ANPR)

Equip the intersections with traffic light crossing violations recording system and video surveillance cameras monitoring traffic flow

Advantages

Cameras are capable of fining any number of offending vehicles simultaneously

Challenges

  • Drivers cover the number plate of their cars daily in order to not to be fined
  • Some drivers who repeatedly pass specific passages try to destroy or damage the cameras and their equipment.

2. Speed violation recording cameras

Fixed cameras equipped with radar technology are assembled to identify and record speed violations

 Advantage

Assured of getting fined through being caught on camera, drivers rarely attempt to drive over the speed limit

Challenges

  • After identifying the locations where the cameras are installed, drivers may attempt to increase their speed in the distances between cameras, and this may cause many disturbances in traffic flow.
  • Due to the weakness of technology, identifying motorcycles is not possible in this system

3. Cameras for recording violations of passing through red-lights at intersections

Cameras are assembled at intersections  to record the red light running violations.

Advantages

A decrease in this kind of violation will have a direct effect in reducing car crashes and capital loss.

Challenges

  • In many intersections, due to the low quality of crosswalks and zebra crossings, it is really hard to determine a threshold running from which enables the driver to be known as an offender
  • As in many intersections, turning left or right is not legally forbidden, it is really a hard job to distinguish the vehicles doing so from the violators.

4. Equipping the transportation system with GPS

Position of the buses and the approximate arrival time of buses to stations can be calculated those who are speeding or using unauthorized routes can be identified

Advantages

  • Reduction of dangerous high speed of buses
  • Decreasing of delay time of journey

Challenges

  • Some drivers try to deactivate the GPS before attempting violation. They cover the GPS with aluminum foil to make it disconnected from the center.
  • Due to the need for a GPRS platform for sending the information to the center, using this system in Tehran is very expensive.
  • Due to the low average educational level of drivers and users of public transportation services, the relevant systematic training for using this system will be needed.

5. Use of intelligent routing systems for public transportation passengers

Passenger can receive information about the journey duration and the best manner of navigation after determining the origin and destination and also specifying the desired transportation mode such as metro, taxi, bus or walking

Advantages

 Decrease in delay of journeys and an increase in productivity.

6.  Modern informative systems for offenders

All fine notifications and notices for a technical test will be informed to the offenders via SMS

Advantages

  • Deliver the fine notifications to the offenders, omitting the process of printing and stuffing envelopes with fine notification
  •  Informing all offenders of their violations in an online manner, and creating a cohesive database of the offenders.

Challenges

  • As the telecommunications system and necessary infrastructure have not been completely developed, some problems in sending the SMS to offenders have been occasionally observed.
  •  Informative limitations such as length of words in SMS.

That’s it about ITS.

Continue learning!

MUST READ: Basic of civil engineering; Simple and in-depth guide

CONCRETE

Construction Joints in concrete – Construction joint types in slabs

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Construction joints in concrete are a crucial and fundamental component of civil engineering and construction. Changes in temperature and moisture can cause concrete to expand and contract. Because concrete is weak in tension, shrinkage and volume change in concrete cause cracks. The construction joints installed at strategic locations prevent the formation of cracks in concrete and the development of tensile stresses. A construction joint is a type of concrete joint used when a new section of concrete is poured next to an already set section of concrete. The purpose of a construction joint is to allow for some horizontal movement while remaining rigid against rotational and vertical movement. This article discusses the significance of construction joint types in concrete structures like slabs and pavements etc and their applications and features

  1. Construction joints in concrete – Significance
  2. Construction joints types
  3. Construction joints
  4. Expansion joints
  5. Contraction joints

Construction joints in concrete – Significance

In general, joints in concrete are strategically placed between slab and beam, wall and column, concrete floors, pavements and so on. Improper use of joints can result in defects, cracks, and the development of stresses. Construction joints can be filled or left empty. The space between joints is occasionally filled with materials like elastomers, bitumen asphalt mix, polysulphide sealents etc. Construction Joints also divide a larger span into smaller units, making construction easier. As a result, it also aids in preventing the total collapse of the structure. Depending on the type of joint, joints are installed either before or after the laying of concrete.

Construction joints types

On the basis of the functions, Joints in construction are classified into three types

  1. Construction joints
  2. Expansion joints
  3. Contraction joints

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Construction joints

Generally, construction is a time-consuming process. Construction joints separate the large concrete work into small units. This type of joint is apt for locations where the construction is stopped at the end of the day’s work. A construction joint is a type of concrete joint used when a new section of concrete is poured next to an already set section of concrete. The purpose of a construction joint is to allow for some horizontal movement while remaining rigid against rotational and vertical movement.Construction joints can be further classified into four types on the basis of the joint end. They are

  • Butt-type construction joint
  • Tong and groove type construction joint
  • Butt-type construction joint with dowels
  • Butt-type construction joints with tie bars
Concrete construction joints in concrete

On the basis of the structure, the construction joint can be vertical, horizontal and inclined. It is suitable for the construction of large slabs, irrigation channels, etc. These joints consist of keys at definite intervals. These keys help in resuming the work the next day. It also helps in uniform load distribution.

Expansion joints

Concrete tends to expand due to changes in temperature and moisture. This causes the development of cracks and leads to failure. To avoid this problem expansion joints are used. Another name for the expansion joint is the control joint. This joint allows the expansion of concrete without the development of stresses. Thus we can prevent cracks. Buildings longer than 45m typically have one or more expansion joints. The recommended c/c spacing in India is 30m. The joints are formed by leaving a space between the building components. Generally, the depth of the expansion joint is one-fourth of the slab thickness. Installation of expansion joints can be done before or after the laying of concrete. Before installing make sure to cut the joints deeply. It is apt between the bridge section, pavements, railway tracks etc. 

Concrete construction joints in concret

Contraction joints

Concrete is weak in tension, therefore contraction of the concrete induces stress leading to cracks. This occurs during the hardening of concrete. Contraction joints prevent the unnecessary development of cracks. This type of joint in construction is installed before the laying of concrete. It is apt during the construction of roads, retaining walls, floors, tunnels, canals, etc. Generally, the interval of contraction joints is between 5m to 10m. Jointing tools are used for the installation of contraction joints. If the concrete is reinforced, then contraction joints can be avoided. But in un-reinforced or lightly reinforced slabs this joint is necessary to minimise the formation of cracks. 

Construction joints in concrete
beams, BUILDING CONSTRUCTION

What is a Plinth beam? Plinth beam height and size

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What is a plinth beam in construction? Plinth beams are horizontal structural elements that are built at the plinth level. It is the first beam built after the foundation has been completed. Furthermore, the plinth beam is an important component in a building because it serves as a foundation for brickwork as well as a moisture barrier, preventing moisture from entering the superstructure walls. The height of the plinth beam is typically 200mm to 450mm. It can be both reinforced and unreinforced.

The most important components of a building are the substructure and superstructure. The substructure is the part of the building that is below ground level, while the superstructure is the part of the building that is above ground level. The plinth level separates the substructure from the superstructure. The plinth beam follows the foundation’s construction. This article discusses what a plinth beam is, as well as plinth level, plinth beam size, and plinth beam height.

  1. What is a plinth?
  2. What is a plinth beam?
  3. Plinth beam in construction – Functions and advantages
  4. Size of plinth beam
  5. Plinth beam reinforcement
  6. Plinth beam construction

What is a plinth?

The plinth is the structural stratum that separates the superstructure and substructure of a building. All structures must have a ground floor that is 45 to 60 centimetres higher than the surrounding ground. This will prevent rainwater, dirt, and dust from entering the building. Because of this, the outer dimensions of a pedestal constructed first are slightly larger than those of the ground floor. That is referred to as the Plinth. A level or base known as a plinth is used to support superstructure walls, columns, and other structures. The plinth’s function is to distribute pressure and load evenly across a surface.

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