All posts by Vinod Gopinath

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

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)”

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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


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 types for road Layers – Bitumen Emulsion types

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 
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.


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.

Aluminium Composite Panel || ACP sheets design

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.


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.


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.


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.


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 in construction – Top 5 Formwork types

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 buildingroadsbridgestunnels, 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

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.


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.


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:

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.


UltraTech Cement commissions 1.9 mtpa cement capacity in Pali – Rajasthan

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.

Types of bonds in brick masonry walls – Advantages and features

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

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.