Properties and different type of Bricks

Brick

Bricks are a common building material used for centuries in construction. They are typically made from clay, shale, or other materials that can be shaped and fired in a kiln to create a hardened and durable product. Bricks come in various shapes, sizes, and colours and are used for a wide range of applications, including building walls, pavements, and other structures.

Brick Size:

• Traditional Brick - 23 cm X 11.4 cm X 7.6 cm (e 9'' x 4.5'' x 3'') 
• The standard size brick/masonry brick size- is 19 cm X 9 cm X 9 cm 
• Nominal brick  or  modular brick or brick with mortar- 20 cm X 10 cm X 10 cm 

Ingredients of Brick:

Ingredients	Percentage
Silica	50-60 %
Alumina	20-30 %
Lime	10 %
Magnesia	<1 %
Ferric Oxide	<7 %
Alkalis	< 10 %

It also consists of a small quantity of iron, Sulphur.

Silica: 

• Helps to retain its shape and size.
• Impart Durability
• Prevent shrinkage and warping

      Excess: excess of silica makes the brick brittle and weak on burning

Alumina:

• It gives plasticity to clay.

      Excess: Provides cracks on drying.

Lime:

• Reduce shrinkage on drying.
• Lime lower the fusion point.
• it helps silica to melt on burning.

     Excess:  excess lime causes the brick to melt and loses its shape.

Magnesia:

•  Gives yellowish colour to the brick.
•  Reduces warping.

      Excess:  Decay on Brick.

 Iron Oxide:

• Provide red colour
• increases  durability 
• Reduce permeability 

Excess: Blackish colour. excess of ferric oxide makes brick dark blue.

Type of Brick:

1. First Class Brick
2. Second Class Brick
3. Third Class Brick

1. First-class brick: 

• This type of brick is thoroughly burnt.
• Colour: Red cherry / deep red/ copper colour.
• It should have a uniform texture.
• Free from flaws, cracks, and lumps.
• No impression should give when scratched by fingernails.
• Sound: when two bricks struck against each other, it gives a metallic sound.
• Water absorption: 12-15 % of the dry weight of brick, in 24 hours.
• Crushing Strength: not less than 10 N/mm².

First Class Brick

Uses:

• Masonry work is exposed to the weather. 
• Flooring Pointing work.

2. Second class Brick:

• Small cracks and distortion are permitted.
• water absorption is a little higher than first-class brick, 16 - 20 % of its  dry weight.
• Crushing strength should not less than 7.0 N/mm².

Uses:

For all types of structures with masonry work.

3. Third  Class Brick:

• Underburnt Brick
• Produce a dull sound when struck two bricks.

Uses:

for temporary structure construction.

 Reference Book: Building Materials by S.K. Duggal