Manufacturing process of Bricks | Simplified - learncivil

Hello, friends today we will study About Manufacturing process of bricks in brief.

The Manufacturing operations of bricks are as follows:
Manufacturing process of Bricks

1)Preparation of clay
2)Moulding
3)Drying
4)Burning

1)Preparation of clay

  • Un soiling
  • Digging
  • Cleaning
  • Weathering
  • Blending
  • Tempering



  • Un soiling:

The surface of the site selected for obtaining brick earth (clay) is cleared by removing the top layer of soil containing vegetable matter, about 200mm in depth. The clay in topsoil is full of impurities and hence it is to be rejected.


  • Digging:

The digging of the earth is generally carried out by manual labour, but for large work, excavators may also be used. The excavated earth is spread on the levelled.

  • Cleaning:

All stone pebbles, gravel, kankar and roots of grass or plants, etc., are completely removed.

  • Weathering:

The clay is then exposed to the atmosphere for softening or mellowing. The period of exposure varies from a few weeks to full season.

  • Blending:

The clay is made loose and any ingredient to be added to it, is spread out at its top. The blending indicates intimate mixing. The blending makes clay fit for the next stage of tempering.

  • Tempering:

In the process of tempering, the clay is brought to a proper degree of hardness. The Tempering
should be done to obtain a homogeneous mass of clay of uniform character.

For manufacturing good bricks on large scale, the tempering is usually done in a pug mill. 
Manufacturing process of Bricks

2)Moulding:

Moulding may be carried out either by hand or by the help of a machine.
Following are the two types of moulding:
i) Hand moulding
ii) Machine moulding
Manufacturing process of Bricks

Also read: Imp Topic - Size and weight of bricks

i) Hand moulding

Bricks are moulded by manually. It is cheap and hand moulding is suitable for small scale brick production.
The mould are rectangular boxes which are open at top and bottom. They may be of wood or
steel.

The bricks are prepared by hand moulding are of two types:
a) Ground-moulded bricks
b) Table-Moulded bricks


a) Ground - moulded bricks

In this process, the bricks are moulded by keeping the mould directly on the ground. Following
operations involved in ground moulding:
1. The ground is first made level.
2. Fine sand sprinkled over it.
3. The mould is dipped in water and placed over the ground.
4. The lump of tempered clay is taken and it is dashed in the mould.
5. The clay is pressed in the mould.
6. The extra clay is removed by metal or wooden strike.
7. The mould is then lifted up and raw brick is left on the ground.
8. The process is repeated until the ground is covered with raw bricks.

b) Table-Moulded bricks:

The process of moulding the bricks is the same as ground moulding but in this case, the moulder stands near a table of size about 2m x 1m. The cost of a brick is more compare to ground moulded bricks as the number of bricks produced per day is less.
Approximately 1000 bricks per day can be moulded by the team of a moulder and his
assistant by this method.


ii) Machine moulding:

Machine moulding is adopted for large scale manufacturing. The types of machines used for
moulding are:
a) Plastic clay machines
b) Dry clay machines

a) Plastic clay machines:

Such machines contain a rectangular opening of size equal to the length and width of a brick. The pugged clay is forced through a rectangular opening of size equal to the length and the breadth of the brick. The clay comes out through the opening in the form of a continuous bar, it is cut into strips by wires fixed in frames. therefore are also known as the wire cut bricks.


b) Dry clay machines:

In these machines, the strong clay is first converted into powder form. A small quantity of
water is then added to form a stiff plastic paste. Such paste is placed in a mould by machine to form hard and well-shaped bricks.

3)Drying:

After the bricks are moulded, they are dried. If bricks are not properly dried before they are burnt, they may get cracked and distorted during the burning process.

Following are the objects of drying the bricks:

a) To remove as much moisture from the bricks as possible, so as to save time and fuel during
the burning.
b) To avoid the chances of cracking and distortion of bricks during the burning.
c) To increase the mechanical strength of the bricks without any damage to the bricks.

Following two methods of drying bricks:

  • Natural drying
  • Artificial drying.

Also read: Imp Topic - Various test on bricksTest on bricks


4)Burning:

This is a very important operation in the manufacture of bricks. It imparts hardness and strength to the bricks and makes them dense and durable. Bricks are heated up to 700 to 1000° C.

At this temperature alumina and silica in the clay fuse together resulting in a compound which is strong and stable.


The purpose of burning is:

1. To impart hardness and strength to the bricks.
2. To increase the density of the bricks so that they will absorb less quantity of water.


The bricks may be burnt in any one of the following:

a) clamps
Manufacturing process of Bricks



b) Intermittent kilns:


c) Continuous kilns.


Clamps are temporary structures, and they are used to burn bricks on small scale, but kilns are
permanent structures and are used to manufacture bricks on a large scale basis.

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