How Are Bricks Made? Step By Step Manufacturing Process Explained

Bricks are generally rectangular-shaped building blocks that are the most integral part of construction; the process of brick making is what determines how sturdy the structure will be in the long run.

It is a type of block, which is required in masonry construction and is used to create walls, buildings, and other structures. Properly, the term brick means a block that consists of dried clay or other construction blocks chemically cured.

Bricks are produced using adhesives, mortar, or even by interlocking them, and numerous classes, materials, types, and sizes are manufactured in bulk. There are different kinds of bricks which include lightweight bricks or blocks, which generally are made from expanded clay, fired bricks are considered to be one of the sturdiest building materials, and air-dried bricks or mudbricks are the oldest bricks used for building.

In this article, you will find a detailed description of the production of, blocks, raw materials required to make blocks, what blocks are shaped like, and the elements of masonry and brickmaking. You will also discover the minerals in blocks, how bricks were made, alternatives to blocks such as blocks made of plastic, additives added to blocks, and the type of blocks desired for the construction of constructions and structures. Lastly, we will discuss the methods and machines required to produce good blocks and building material, the type of brick used in the old times, what bricks contain and how building blocks were made years ago, the brick industry, and the like.

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What is the raw material used in making bricks?

Bricks are generally made out of clay and other additional materials that differ from brick to brick.

Bricks are rectangular building blocks that have been used as building materials for thousands of years to preserve constructions and other structural constructions.

Bricks are manufactured either by hand or by machine. The process of creating bricks requires primary raw materials, like clay which is further ground into particles, and water, which forms a paste. They are further given the required shape and pressed into molds to acquire sharper edges. They are then fired in high heat to make them stronger by burning them and then dried in natural light. During ancient times, bricks were generally made by hand.

What are different types of bricks?

There is a wide variety of bricks that are used for various purposes.

Sun-dried or unburnt bricks are used for temporary structures and not for permanent structures because they are not very durable as they have less water and fire resistance. The process of preparing these bricks involved clay preparation, molding, and drying using natural heat.

First-class bricks are better bricks that are produced by the process of table-molding and also by burning them. These bricks contain a conventional shape and have more strength. Therefore, they are used for permanent constructions.

Second-class bricks are of moderate quality and are molded using the ground-molding process. They have a rough exterior and sharp edges as well therefore, smooth plastering is required.

Third-class bricks are poorer in quality and are not exposed to any heat, therefore making them unsuitable for rainy areas. These ground-molded type bricks are made on the ground and therefore are rough.

Fourth-class bricks are the cheapest and the worst bricks, which are crushed and used as additives that are mixed while manufacturing concrete. They are discarded bricks that are the result of over-burning and are not suitable for construction because they are very brittle.

Fly ash bricks are created when fly ash and water are mixed together and are known to be better than clay bricks. They have a high calcium oxide content, which is the main bricks' raw matter in cement making. They are light and reduce the weight of the edifices that are built with them. Hence, in many instances, it is called a self-cementing brick. They have high strength, great fire insulation, and their uniformity in size is better for plaster and joints during masonry construction. 

Concrete bricks are created by using concrete and other key ingredients like sand, cement, coarse aggregates, and water. These bricks are better than clay bricks and can be easily produced by a machine in any construction site, which reduces the quantity of mortar required while in production thereby making them lightweight.

Engineering bricks are the strongest bricks used and have high compressive strength with great frost and acid resistance. They are predominantly used to make basements damp-proof.

Calcium silicate bricks consist of lime and sand and are called sand-lime bricks, which are mainly used for ornamental works on walls and in masonry. 

Phases Of Manufacturing Bricks

Brick manufacturing goes through a sequence of phases, which are important to make the brick sturdy and suitable for use.

First, the elements and raw materials used to create bricks per batch of bricks are ground by pulverizing them with steel hammers in the hammermill. Vibrating screens control the perfect size of the material by separating the improperly sized ones.

The second manufacturing process is extrusion. Extrusion is the process in which the material is mixed with water and further cut and folded to make wet clay. This blend of clay and water is further fed into an extruder which removes air from the mixture to prevent the bricks from developing any cracks or other defects. It is then compressed and further shaped into the desired shape through a die orifice.

The third process is chamfering the brick with chamfering machines. These machines have rollers that help indent the brick while it is extruded. These machines produce approximately 20,000 bricks per hour.

Fourthly, the bricks are further coated with a sand coating. There is a continuous, vibrating feeder, which helps coat the brick with soft material. Compressed air or a pressure roller is used for harder materials. As for notably harder materials, the bricks will require sand-blasting.

Drying is the next step. Before the brick is fired, it has to be dried to remove any moisture present in the wet and ground clay. It is imperative to remove this moisture otherwise the water present in the bricks will burn off too fast during the process of firing in the kiln, which might result in cracking. Two kinds of dryers are generally used for the drying process; tunnel dryers, which use cars and fan-circulated hot air to speed up the drying process, and automatic chambers, which are predominantly used in Europe. These extruded bricks are placed in rows automatically on two bars parallel to each other, which helps to transfer the bricks into the dryers by transferring cars that are rail-mounted or by lift trucks.

The next process is firing. After the bricks are completely dried, they are loaded on cars and fired at a high temperature in furnaces, which are called kilns. They come in several shapes with the tunnel shape being the most common. Most kilns present in the United States utilize gas as fuel for the firing process. Only a few brick kilns produce bricks by the methods of firing them using solid fuels like coal and sawdust. Over time, however, the design of the kiln has been adapted to preserve fuel.

The next stage is setting and packaging the bricks after they are fired and then cooled. Manual brick handling is not carried out anymore and the bricks are usually loaded onto cars automatically. The bricks are set into rows and the stack is secured with steel bands and is also fitted with plastic strips that help protect the corners. These bricks are then shipped to the site and typically unloaded with the help of boom trucks.

The last stage of brick manufacturing is quality control. The brick industry is very important industry and the bricks they provide need to have durability and strength in order to ensure that the building constructions made by using them stay secure. It involves setting control limits for specific processes like the temperature while firing or drying and keeping track of the parameters to make sure that the limits of the concerned processes are maintained. This further prevents defects and improves yields.

Properties Of A Good Brick

A good brick should have certain properties that determine how high its quality is.

Good bricks should be adequately burnt and should be rich-red or copper in color. Over or under-burnt bricks lose their shape and are not suitable for construction. They should be uniform-sized, not be bulky around the edges, and should be sharp. They should be able to resist scratches, be compact, uniform, and possess zero lumps. It should absorb less than 20% of water when it is submerged in it for 24 hours. They should not have any salt deposits on their surface. This can be determined by looking for white patches on the bricks and will not be suitable for construction. Soils that are used in manufacturing bricks should not have any potassium, sulfate, and sodium content and might lead to efflorescence, which is surface disruption of the bricks due to the presence of harmful salts. The brick should not have any kankare, stones, or other chemicals.

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