Bricks – Its types, Tests and uses
Bricks
The material used for the making of walls, pavements & other elements in all construction called brick. This is very old building construction.
It is also the most durable material. There are many walls which are made up of these bricks, it is also used in the foundation & pillars. The roads constructed by using it, thousands of years ago are still in good condition.
It is rectangular blocks in shape & used for the building parts, making walls in other constructions.
Today It is still common for the construction because they are small in size & can easily be handle. The bricks are durable and stronger in compression and also they can be built into complex shapes.
Materials Used For Making It
The main materials used for making the brick are:
1: Clay:
The deposit of alluvial found in the areas of lowland is known as clay. There are serval main types of clay, such as:
2: Strong Clay:
Strong clay is full of natural moisture contents which renders them into the plastic, & it is suitable for the hand modeling.
3: Sandy clay:
sandy clay contains silica and is shrink less.
4: Calcareous Clay:
calcareous clays are the clay with lime, these clays are used for making the good bricks and varying or changing it from pink to dark red.
5: Calcium Silicate:
They are made up of a mixture of hydrated lime, water & silica sand. This presses it into the shape & then the pressure steam baked in an autoclave which produces a white, dull & a regular brick.
Types of brick & Uses
There are the following 5 types
- Burnt Clay
- Concrete
- Fly Ash
- Fire bricks
- Sand Lime
1: Burnt Clay Brick:
The classic form of brick is the burnt clay. These types of brick are created by pressing the wet clay into the molds then these are drying and firing in the kilns. This material is the oldest building material, these bricks are the solid blocks of hard clay & reddish in color.
These have the best quality and good strength but costly.
Uses
They are solid blocks and have good quality & strength, so these are used in the foundations, columns & masonry walls.
2: Concrete Brick:
The solid concrete is used for making it. These bricks are placed in fences, which provide a good presence. During production, if the pigments are added, it provides different colors. So, these are manufactured to provide different colors.
Uses
They are used in Fences & in hidden brickwork.
3: Fly Ash Brick:
Fly ash brick is made by fly ash (coal burning at 1000 centigrade) and clay. There is a high volume of calcium oxide in fly ash. It has the advantage of lighter weight than concrete and clay type.
Uses
They are used in pillars, foundation, structural walls and anywhere where fire resistance is required.
4: Fire Brick:
They are made up of specially formulated earth with high aluminum content. They have the ability to stand with high temperatures without changing their shape, size, and strength after burning.
Uses:
These are mostly used in chimneys, fences, pizza ovens, and outdoor barbecues.
5: Sand Lime Brick:
They are made by the mixing of fly ash, lime, and sand. For the color pigments may also be added, Than the brick is formed by applying pressure on the mixture. The chemical reaction takes place and provides wet bricks that are dried under heat and pressure.
Uses:
Sand lime is used in fences and hidden brickwork.
Shapes of Brick
They can be classified by their shapes, such as;
- Brick Veneers
- Air
- Bull Nose
- Paving
- Capping
- Hollow
1: Brick Veneers:
These types are thin and used in the surface facing.
2: Air bricks:
To circulate air and less weight these type of bricks contains large holes, used in cavity walls and floors.
3: Bull Nose Brick:
Round angles with molded brick.
4: Paving Bricks:
This type is used in underfoot paving.
5: Capping Brick:
The top of the freestanding walls are caped or covered by using it.
6: Hollow Brick:
They are used in partition walls where load-bearing is not required.
Compressive strength of Bricks
- 105kg/cm is the strength of first-class brick.
- 70kg/cm is the strength of second class brick.
- 35kg/cm is the strength of common building brick.
- 15 to 25kg/cm is the strength sun-dried brick.
Tests of brick
There are the following tests Which mainly perform
1: Absorption Test
To find the moisture absorbed by bricks under extreme conditions the absorption test is applied on the brick.
The amount of water absorption should not exceed 20% of the weight of dry brick for a good quality brick.
2: Crushing Strength Test
By placing a brick in compression
The test machine the crushing strength test is determined.
3.50N/mm2 is the minimum crushing strength of brick.
3: Hardness Test
Against sharp things, a good brick should resist scratches. A sharp tool is used to make scratches on brick for this test if the scratches do not occur then it is said to be hard brick.
4: Shape & Size Test
The size and shape of it are most important and all it should be the same for the contraction. The shape of the brick should be rectangular with sharp edges.
The standard brick size is length 19cm, breadth 9cm, height 9cm.
5: Color test
Good brick should be bright and uniform in color throughout its body.
Manufacturing Process
There are four steps involved in the manufacturing process.
1: Preparation Of Clay
For the preparation of the bricks, we need pure clay. The top layer of the soil may contain impurities.
After removal of the top layer, from the ground, the clay is dug out and spread on the plain ground, then the stones and other materials are removed from the clay. For the softening cleaned clay is exposed to the atmosphere. Then water is added to the clay and mixed.
2: Molding
The prepared clay is mold into the rectangular shape. There are two ways to do this process such as;
- Hand Molding is for the small scale
- Machine Molding is for the large scale
3: Drying
The bricks contain moisture after the molding process so the drying is done otherwise they may be cracked while burning.
4: Burning
After drying it, it should be burnt in kilns at a specific temperature of 1100c, by doing this the brick gain hardness and strength.
Advantages
There are many advantages of bricks construction.
- Strength
- Porosity
- Fire Protection
- Sound Attenuation
- Isolation
- Wear resistance