Bricks have been used in the construction industry for decades. Some of the most sturdy and ancient buildings in your town were made of bricks. They age slowly and can withstand different weather conditions.
In this article, we look at how bricks are made step by step. Let’s get into it!
- Collection of raw materials
- Weighing and batching
- Feeding and mixing
- Mixing unit to mold block
- Types of bricks manufactured
- Hollow bricks
- Paving bricks
- Interlocking bricks
- Solid bricks
- Porous bricks
- Clay bricks
- Fly ash bricks
- Concrete bricks
- Sand lime bricks
- Engineering bricks
- How clay bricks are made?
- Why use bricks for your construction needs?
Well, the making of bricks follows a particular order. However, the specifics of each type of bricks, such as clay, may differ in some processes, which we will cover in depth in the following section. So, what happens between the extraction of raw materials and the formation of bricks? Let’s find out!
Collection of raw materials
This involves looking for the main ingredients that will make the blocks. Here, companies collect sand, cement, clay, fly ash, and other materials. For example, while the clay is extracted from the ground, fly ash is collected from power plants that use coal to generate electricity since it is a by-product of burnt pulverized coal. On the other hand, companies can get cement from local suppliers.
Weighing and batching
Once the crucial raw materials, they undergo weighing so that they can meet the required weight before batching. They can be stored in cement silos, stationary, or mobile batching plant. This allows for easy access when they are needed for mixing.
Feeding and mixing
Now, the brick making plant starts making blocks from this stage. The materials – raw materials, water, and adhesive – are transported to the mixer. This can either be manually or automatically depending on the model of the plant.
Once fed into the mixer, the mixer – again, either automatically or manually – mixes the ingredients uniformly. This is to ensure they are of high density and quality.
Mixing unit to mold block
The mixture is then transported to the hopper using a conveyer belt. Once in the hopper, it finds its way to the mold block where through a combination of vibration and hydraulic pressure, compact and high-quality bricks are made.
The bricks laying on the pallets are transported to a storage area by manual carts.
This is how bricks are made step by step. Below is a brick manufacturing process flow chart that will better help you grasp this process.
Types of bricks manufactured
You can get different types of blocks depending on the raw material used and the shape. First, let’s look at the shape classification.
These are commonly used in the construction of wall partitions since they are lighter compared to other types of bricks. Besides, they are faster to make, cost-effective, eco-friendly, and easy to install, not to mention their stellar sound insulation property.
As the name suggests, they are mainly used in the construction of pavements and parking spaces. They are primarily made of cement or concrete thanks to their toughness. Also, they come in different colors.
This type mitigates the need for plastering since they utilize the lock mechanism to lock into each other. They are also resistant to earthquakes, provide heat insulation, and are easy to make compared to solid bricks.
These are blocks that are used for conventional construction needs. They can be used on walls or cladding. They can be of different materials such as clay, cement, or concrete.
These hollow blocks are made of clay, sand, and an adhesive material. They undergo burning and cooling ensuring they are of high strength. This makes them an ideal option for both commercial and domestic use since they mitigate structural shrinkage.
This can come in two types: sun-dried and burnt blocks.
Sun-dried/unburnt clay bricks
These bricks are fragile and are not recommended for commercial use. You can use them in partitioning a house but not for walls or fences. Why? Because they are less resistant to water. They are formed through clay preparation, molding, and sun drying.
Burnt clay bricks
This is one of the most popular bricks in the construction industry. In fact, most ancient buildings are made of this type of clay bricks. They undergo pressing in molds, drying, and firing to form high strength bricks.
They are usually red. While they are preferred to unburnt bricks, they also come with some defects and it is for this reason that they are classified into four categories – first to fourth class. The first class bricks are of high quality compared to the fourth class.
Compressed Earth Blocks
This earth blocks is made of earth soil and a little cement. And soil earth block is very popular in Africa and South America. This earth blocks can be interlocking and hollow type. You need to use a compressed earth block machine to produce these soil bricks.
Fly ash bricks
They are made from fly ash and water. They are more durable compared to clay bricks. They also consist of calcium oxide used in cement production that further bolsters their strength. Most construction experts prefer fly ash bricks due to their lightness that reduces the weight of the structure on the foundation.
You can also get fly ash clay bricks that are of higher quality. Some of the benefits of these bricks include heat and noise insulation, uniformity, and easier preparation. They can be used in wall, pillar, and foundation construction.
Another staple type of bricks in the construction industry are concrete bricks. Their main ingredients include cement, sand, water, and coarse aggregate. The best part: they can be manufactured on a construction site with ease. They can be used to construct walls, fences, pavements, and other structures.
Sand lime bricks
They are manufactured using lime, sand, and fly ash. As the mixture is exposed to pressure, they bond through a chemical reaction forming high density and tough bricks. Color pigments can also be added to the mixture to improve its aesthetic aspect.
Some of the advantages of using these bricks include the ability to withstand high loads, uniform and smooth finish, easy to make, and more. They are also used in making ornaments when color pigments are added.
These are specialized bricks that are used for specific construction needs. They have a high aluminum oxide content enabling them to withstand high and extremely low temperatures. You are likely to find them in basements and chimneys.
How clay bricks are made?
Clay bricks were among the first concentration materials man used. This is thanks to their availability and ease of manufacturing. Now, to manufacture bricks made of pure clay you should follow this process
To get pure clay, we need to remove the top soil. It is also referred to as clay unsoiling. The soil of up to a depth of 200 mm is removed since it contains impurities that may hinder the manufacturing of quality bricks.
Once the top soil is removed, digging and spreading of the clay soil commences. It is dug out and spread in 600 or 1200 mm heaps on level ground.
Once spread, it is time to clean off particles such as vegetables, twigs, stones, and other physical impurities. This is the most tedious process, especially if the clay soil contains excess physical matter. In such an event, washing and screening should be conducted. The clean heaps are then crushed into powder using rollers.
This process involves exposing the clay powder into the atmosphere. This is in a bid to soften it bolstering the strength and plasticity. Weathering can last between 2 to 4 weeks depending on the weather. Most experts recommend digging the clay before the rainy season for optimal results.
Here, we improve the quality of the clay by adding other materials such as ash, sand, coal, and others.
Now it’s time to add adequate water to form a homogenous mixture. The clay is subjected to pressure either by men’s feet, cattle, or pug mill (for large projects). This is in a bid to blend all materials and give it a smoother feel. Once done, the clay is ready for molding.
In this stage, the prepared clay is molded into bricks of different sizes and shapes. Here, you can opt between hand and machine molding. The catch: the former is labor-intensive while the latter, although ideal, can be expensive for small projects. Let’s have a look at both.
As mentioned above, hand molding is ideal for small projects. It is also cheaper compared to machine molding. You can choose between ground and table molding.
The ground molding requires you to first, level the ground and sprinkle ash or sand. Second, place the wet mold and fill it with the clay. Third, press and distribute the clay to form an even block. And finally, remove the mold to be left with the molded clay brick.
Table molding is similar to ground molding only that you perform it on an elevated platform. Ideally, you should use a 2m x 1m table. Of the two, hand molding is more economical.
As expected, you’ll use a machine to make bricks. This method is efficient compared to hand molding since you can make many bricks within a short period. Besides, there are numerous machines to choose from. For example, you can choose an automatic, semi-automatic, mobile, or hydraulic machine.
Here, we can either use plastic and dry clay machines. Let’s see how they work.
The plastic method ideally uses a machine that has a rectangular opening. Once the tempered clay is fed to the machine, it comes out of the opening. Now, as the brick approaches the opening, a beam of wire cuts it into smaller blocks.
The dry method is more economical and time-saving. In fact, the machine can temper the clay mitigating the need for human input. The tempered clay is then fed into a mold which, through vibration and hydraulic pressure forms bricks. These bricks are of higher density and ideal for commercial use.
You might think the bricks are directly burnt after this, but this is far from the truth. They need drying, otherwise, they would get damaged. You can choose between the natural or artificial drying process.
The natural process involves spreading them in uniform columns in an open space. Ensure there’s ample air circulation between bricks for optimal drying. This should take at least 10 days depending on the weather.
The artificial drying process is preferred for large scale production and in wet environments. Special dryers are used to dry the bricks.
This is the most important stage of clay brick making. The bricks are fed into clamps or kilns and subjected to heat up to a certain temperature. Ideally, you should subject them to temperatures between 700 degrees and 1,000 degrees. This is to enable both physical and chemical changes. As such, they become stronger and stable.
Some of the kilns used include:
Open kiln: this type is temporary and is used to burn not so many bricks. It is also cheaper to construct and does not require extensive human input.
Intermittent kiln: it is ideal for large brick production factories. However, the burning process is not continuous.
Continuous kiln: this is what most behemoth clay brick manufacturing companies use. It offers continuous burning and you can choose between Hoffman’s, tunnel, and Bull’s Trench Kiln.
After burning, the clay bricks are ready for storage and use.
Why use bricks for your construction needs?
While most building materials are known to cause pollution, most bricks fuel sustainable construction. For example, the production of fly ash bricks in fact uses waste material hence conserving the environment. Besides, clay bricks do not produce CO2 as is the case with concrete.
- Energy efficient
Most brick houses spend less on heaters and coolers. Why? Because bricks are excellent heat insulators. This means they can prevent loss of heat during winter and prevent excess heat during summer. So, if you want to cut your electricity bills, it’s time you went for a brick house.
Some of the most standing ancient buildings were made of bricks. A brick wall can last for decades without showing signs of cracking. Besides, they evenly distribute the weight of the structure preventing the foundation from crumbling.
- Improve the aesthetic aspect
Whether it is a building or a parking lot, bricks are known to improve the uniqueness of spaces. This is because you can add color pigments and also use different shapes in different spaces.