Basic Composition of Bricks

Finding good quality bricks is a difficult challenge for every homeowner, architect, builder, and civil engineer. Good quality bricks form an integral part of your home, and hence quality matters the most when it comes to picking the right composition of bricks.

If the building bricks are produced from good quality materials, they will provide long-term durability along with offering high compressive strength to your home.


What are Bricks?

Bricks are hard materials produced from sun-dried clay and these are rectangular in shape. For building bricks, the clay needs to be molded in rectangle shapes that are uniform in size. Then these bricks are dried and burnt for obtaining hard rectangular-shaped materials that are referred to as bricks. Since the bricks are uniform in size and shape, hence it requires no machine or appliance to lift them.

Using bricks as a building material is easy since it is a cheap, easily available, strong, and durable material. Bricks come in different colors, and consist of different elements, and the properties of bricks are also different in nature.


Composition of Bricks


Composition of Bricks

Below are the composition of bricks in detail:

  • Alumina – Alumina forms the chief element for making bricks. Normally, good-quality bricks should comprise 20%-30% of alumina. This percentage of alumina offers plasticity to the clay for molding purposes. However, if the amount of alumina is more along with the insufficient amount of sand, it might lead to warping and shrinking of the bricks.
  • Silica – This material can be used either as a combination or even as a free material. Like free sand, silica is too mixed with clay, and alumina to form a chemical composition. Good quality bricks should contain about 50%-60% of silica. If the silica or more or less in composition, it might lead to shrinking and warping of the bricks. Not only this, it offers uniformity in shape and makes it more durable in nature.
  • Lime – Another important component of a brick is lime, and the quantity should not be more than 5%. Besides, it should be mixed in a finely powdered state to minimize the chances of flaking the bricks. An excess amount of lime in the composition can make shrink the raw bricks along with losing their shape.
  • Iron oxides – The third important component of bricks is the presence of iron oxides. The amount should not exceed 5-6% in good brick quality. It enables the lime to mix with sand and clay. It also provides a reddish color to the bricks. The presence of excess amounts of iron oxides can make the bricks blackish or bluish in color. Contrary to this, if the amount is less it will make bricks yellow in color.
  • Magnesia – The presence of magnesia offers a yellowish color to the bricks along with minimizing the chances of shrinkage.


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