Brick is considered as the foundation stone constructing a building. It would not be wrong to say that is the oldest material which is used during the construction of a building. According to the research of an archeologist bricks are being used since the 7000BC. Bricks use had been found in the southern parts of Turkey and around Jericho. In earlier times, bricks were sun dried mud bricks they were kept under sun until they were strong enough for use. There is two type of use of bricks. One is constructing the building and second is for the decoration of buildings. Fired bricks were found to be more resistant to harsher weather conditions, that made bricks much more stronger and reliable brick for use in buildings, where the mud bricks would not have been suitable. Fired bricks were also very useful for absorbing the heat generated throughout the day, then releasing this heat at night. Fire bricks are generally yellow in colour and used in places where they would be subject to high temperatures
Classification of Bricks
There are nine main kinds of bricks. They are classified on the base of material use in it. The name of types is:
- Dry pressed bricks
- Calcium-Silicate bricks
- Extruded bricks
- Concrete bricks
- Clinker brick
- Hollow, Terracotta or Tile
- Wirecut extruded bricks
- Stock bricks
- Fletton or London Brick
Composition of Bricks
The quality of bricks depends upon the clay type used in manufacturing brick. Normally, the clay is used that contains sand particles, silicate and alumina. It also contains small quantities of lime and iron oxide. The above mentioned elements play important role and make the brick useful for us. The benefits of these elements are given below:
Silica: It prevents bricks from cracking, shrinking and warping.
Sand: It a brick’s material is sandier than it will be more textured and shapely.
Iron Oxide: this enables the silica and alumina to fuse and adds hardness and strength in bricks.
Lime: when used in bricks making it has two effects. Firstly, it stops the raw brick from shrinking and drying out. Secondly, it acts like a flux during the burning of the bricks. During the burning process, it become the cause to melt the silica and creates the bond which binds all the elements. However, be careful about the quantity of lime in brick making. The excess of lime may cause the brick to melt and loose the shape.
First of all, the clay, water and additives put into a large pit and mixed. The clay is removed and pressed into moulds by hand. The sand or the water is used in the mould to prevent the brick sticking to the mould. After that the brick is laid down to dry by air and sun. Usually, it takes three to four days to dry. After that bricks are put into the kiln for burning. When the burning process completed it is put into water of indentation how ever it is considered very undesirable
Modern Ways of Manufacturing Bricks
Bricks are now more generally made by large scale manufacturing processes using modern machinery. It is a very large scale efforts and produces bricks which are burned in patent kilns.
- The soft mud process
- The stiff mud process
- The dry clay process