Bricks are small rectangular blocks that are used to form parts of structures or buildings, ideally walls. Its history dates back before 7000 BC when they were made by hand-molded mud and left in the sun to dry. Nowadays, they are obtained by molding clay in regular rectangular blocks. These blocks are dried and then burnt to get pucca bricks ready for use in masonry work. The construction carried out using bricks and mortar is known as brick masonry. A brick bond is an arrangement of bricks in a course by which the formation of continuous vertical joints, both in the face and body of the wall can be prevented. Else, they will not act homogeneously and will not distribute the imposed load effectively. Therefore, the strength of masonry work gets greatly reduced.
What are the types of Brick Bonds?
There are numerous different bonds in brick masonry work and each has its look, establishment difficulties, and on account of walls, underlying contemplations. Most bonds require bricks or other masonry units of a comparative size or, more than likely viable sizes. The most commonly adopted bond in brick masonry is the English Bond. In this bond, the alternate course shows headers and stretchers. When seen laterally, a course will show either only headers or only stretchers.
A quoin closer should be provided after the first header in each header course to break vertical joints in successive courses. If one wants to opt for a better appealing brick bond, one may go with a Flemish Bond.
Here, every course consists of headers and stretchers placed alternatively. To break vertical joints in successive courses, queen closers are inserted in alternate courses next to the queen header. For curved surfaces of brickwork or footings in foundations, a Header Bond is provided where all the bricks are laid as headers on the faces. Similarly, a Stretcher Bond has all the bricks laid as stretchers. It is used in the construction of half-brick thick cavity walls and partition walls only. A Facing Bond has a header course laid after several stretcher courses and is mostly used in the case of thick walls.
Sometimes, bricks are also laid in an inclined orientation with the facing of walls for better aesthetic appeal. This type of bond is known as a Raking Bond. A modified form of English Bond, called English Cross Bond is constructed from a ‘beauty’ point of view. It has everything similar to an English Bond but has a header placed next to the quoin stretcher in each alternate stretcher. A Brick on Edge Bond is used for the construction of partition walls. Since these walls are thin, bricks are laid on edge and not on the bed which makes it quite economical as the number of bricks and mortar is reduced. Another modified form of English bond is a Dutch Bond where the quoin of the stretcher course is used as three-quarters of a brick length and a header is introduced immediately after three-quarter bat in every stretcher course. For garden walls, compound walls, boundary walls, etc. a Garden Wall Bond can be used with just one brick thick wall either in English bond or Flemish bond fashion. For the same type of walls, a Silver Lock Bond can also be provided in which every alternate course is constructed by using bricks on edge lengthwise with a cavity in the bricks. Every course is covered by a header course to provide stability to the wall.
DIFFERENCES BETWEEN ENGLISH BOND AND FLEMISH BOND
Types of Bricks
1. Clay Bricks
Burnt clay bricks are the oldest and most-commonly used building material. These are superior quality bricks and are used in the construction of many vital structural members like walls, columns, foundations, etc.
Burnt bricks are classified into 4 different types, these are:
- First-Class Bricks – This category of burnt clay brick is compatible with all the qualities of good bricks. These are table molded and are burnt in furnaces. These bricks hold general shape, smooth surfaces, and sharp edges and are more durable and have more strength. These are used for important work, load-bearing works pavements, flooring, load-bearing walls, etc.
- Second-Class Bricks – These bricks are of moderate quality. Being ground-molded and then burnt in kilns, these bricks have irregular shapes and the surface is rough. Since these bricks are used in areas where the brickwork is coated with plaster, these bricks develop hair cracks. They are mainly used in the construction of flats where a large quantity of the product is used.
- Third-Class Bricks – As the name suggests, these are poor-quality bricks that are normally used for structures that are temporarily constructed. These bricks are not suitable for areas that receive a lot of rain. Third Class bricks are molded on the floor and are then burnt in clamps. The surface of this category of bricks is rough and these have unfair edges.
- Fourth-Class Bricks – These are over-burnt, irregular-shaped, and dark in color. These bricks are used as aggregates for concrete in foundations, roads, floors, etc. Owing to their compact structure, these bricks are sometimes found to be stronger than first-class bricks.
2. Wire Cut Bricks
Wire Cut bricks are made by cutting a segment of clay with wires before they are finished. These bricks arrive in a wide scope of materials and finishes and are exceptionally modest because of their automated fabrication process. These bricks are usually involved by a wide range of structures for individuals who have a more modest financial plan. These bricks are made by hand by talented experts by tossing dirt into molds making every brick exceptional to each other. These are often utilized for the most alluring notable structures making these blocks exceptionally appealing and just for the top-of-the-line housing projects.
3. Stabilized Earth Blocks
Stabilized Earth Blocks or Compressed Earth Blocks are made fundamentally from damp soil compacted at high strain to shape blocks. Compressed earth blocks utilize a mechanical press to form blocks out from an appropriate blend of dry inorganic subsoil, non-expansive clay, and aggregate. The blocks are then stabilized with a chemical binder such as Portland cement. They are mostly used on walls using normal bricklaying and masonry techniques.
4. Hollow Bricks
Hollow bricks also known as Porotherm Bricks is a new class of bricks that has gained immense popularity in the construction industry. Porotherm HP (Horizontally Perforated) bricks are 60% less weighted than a concrete solid block. There are even more advanced hollow bricks packed with a special insulating material called Porotherm Thermo Brick. Being hollow from the inside, these bricks are light in weight enabling faster construction, easy handling, and reducing the dead load of the structure. Hollow bricks are eco-friendly construction materials as they are manufactured by recycled waste and materials like coal ash, rice husk, and fly ash and hence, are certified by the Green Building Council of India. Even though they are light in weight, they have a good compressive strength that can be used for both partitions as well as load-bearing walls.
DIFFERENCES BETWEEN CLAY BRICKS AND HOLLOW BRICKS
BRANDS PROVIDING BRICKS IN INDIA
- Wienerberger Group - Wienerberger is a global provider of building materials and infrastructure solutions with its headquarters in Vienna. They are the only multinational producer of clay blocks for walls, bricks for facades and clay roof tiles, plastic and ceramic pipe systems as well as concrete and clay pavers. They are the world’s largest producer of clay blocks and the company holds leading market positions in our other business segments as well. Founded in 1819, they had nearly 200 years of successful business with over 195 production units across 30 countries. Under the brand name ‘Porotherm Smart Bricks’, Wienerberger India has been producing a range of perforated/ Hollow Clay Blocks that aid in cost-effective wall construction. All blocks are available in 3 sizes (400 x 200 x 200mm) and come in half-block versions as well.
- Durgamba Bricks - Durgamba Build Solutions Co., is an ISO 9001-2015 certified company manufacturing varieties of Clay & Fly Ash Products operating Pan India having its Head Office at Shivamogga and the Branch office at Bengaluru, tried and trusted time to time again from the trade professionals as well as architects and designers. Their manufacturing units are well equipped with modern technology, skilled laborers with high production capacity having best in class logistics to ensure the best quality services for customer satisfaction. The Clay Table Mould and Wire Cut bricks are manufactured with standard size and are burnt using coal in running chambers under are in the name of -“BBI” and “MBW” respectively and the Exposed and other clay products are in round Kiln without a name.
TESTING OF BRICKS
Bricks, like any other building material, are prone to damage from various sources and can also have manufacturing defects which may lead to failure of structure wherever the bricks are used. Therefore, it becomes necessary for the builder/contractor to test the bricks before they are used. The Indian Standard (IS) Code IS:3495 – 2019 is the latest IS Code of practice for testing of bricks and major brands use this code for their testing and certifications as well. The common testing practices for bricks are provided below. It should be noted that not all tests of bricks require a laboratory. Some of these tests can be done on-site by anyone to check their quality
1. Absorption Test on Bricks
An absorption test is directed on a brick to figure out how much dampness content is consumed by the brick under outrageous circumstances. In this test, test dry blocks are taken and weighed. After weighing these bricks are placed in water with full immersion for a period of 24 hours. Then weigh the wet brick and note down its value. The difference between dry and wet weights of the brick will give the amount of water absorption. For a good quality brick, the amount of water absorption should not exceed 20% of the weight of a dry brick.
2. Crushing Strength / Compressive Strength Test on Bricks
The crushing strength of bricks is determined by placing a brick in a compression testing machine. After placing the brick in the compression testing machine, apply load on it until the brick breaks. Note down the value of failure load and then find out the crushing strength value of brick. The minimum crushing strength of brick is 3.50N/mm2. If it is less than 3.50 N/mm2, then it is not useful for construction purposes.
3. Hardness Test on Bricks
A good quality brick should withstand engraving against sharp things. So, for this test, a sharp tool or fingernail is used to make a scratch on a brick. If there is no scratch impression on brick then it is said to be hard brick. This test can also be done on-site and can be done by anyone.
4. Shape and Size Test on Bricks
The shape and size of bricks are very important considerations. All bricks used for construction should be of the same size. The shape of bricks should be purely rectangular with sharp edges. Standard brick size consists of “length x breadth x height” as “19cm x 9cm x 9cm” and nominal brick size should be “23cm x 11.5cm x 7.5cm”. For this test, select 20 bricks randomly from the brick group and pile them along their length, breadth, and height and analyze. So, if all bricks are similar in size then they are qualified for construction work. Similar to the previous test, this can also be done on-site.
5. Colour Test of Bricks
A good brick ought to have bright and uniform color all through its body.
6. Soundness Test of Bricks
The soundness test of bricks shows the nature of bricks against sudden impact. In this test, 2 bricks are chosen randomly and stuck with one another. The sound produced should be a clear bell ringing sound and brick should not break. The brick following these characteristics is said to be a good brick.
7. Structure of Bricks
To know the structure of brick, pick a brick randomly from the group and break it. Notice the inner portion of the brick clearly. It should be free from lumps and homogeneous.
8. Efflorescence Test on Bricks
A good-quality brick should not contain any soluble salts in it. In the event that dissolvable salts are there, it will cause efflorescence on the brick surfaces. To know the presence of dissolvable salts in a brick, place it underwater for 24 hours and dry it in a shaded area. After drying, observe the brick surface thoroughly. If there are any white or grey color deposits, then it contains soluble salts and is not useful for construction.
Bricks have been utilized for building countless designs over a long time due to their sturdiness. Dissimilar to different materials, bricks are very user and upkeep amicable making energy-effective structures yet additionally filling different roles. No big surprise that for quite a long-time modelers and clients show some care for blocks. Bricks don't just oppose the attacks of time yet, in addition, are constantly being reinvented.
Bricks are the most common material used in construction. You can check out the variety of brick sizes and types on Arkihive. Also, you have free and easy access to numerous construction material types on the Arkihive app.