Important Points About BRICKS

Bricks

• Minimum Crushing Strength for 1st class brick- 10N/mm2.
• Minimum Crushing Strength for 2nd class brick- 7.5N/mm2.
• Minimum Crushing Strength for 3rd class brick- 5.5N/mm2.

⏩ Constituents of Bricks

1. Silica (60%):

• Prevents Cracking, Shrinkage & warping of brick. 
• keep it in uniform shape.
• If present in excess it will destroy the cohesion between particles & brick becomes brittle.

2. Alumina (25%): 

• Alumina in bricks imparts plasticity.
• If  present in excess it causes Shrinkage & warping during drying and becomes Brittle during burning.

3. Lime (4-5%):

• Prevent shrinkage.
• If present in excess it causes melting of bricks and also loses the shape of bricks.

4. Magnesia(1%): Provides Yellow tint color to Bricks.

5. Iron-Oxide(5-6%): Provides reddish color to Bricks.

⏩ Standard Size of Brick

• Without Mortar- 19cm x 19cm x 9cm.
• Nominal Size(with mortar)- 20cm x 10cm x 10cm.
• Adopted Nominal (Traditional)- 23cm x 11.4cm x 7.6cm.
• 1 m3 Brick➝ 1800 Kg
• 1 m3 Brick➝ 500 numbers
• 1  Brick➝ 3.5 Kg

⏩ Absorption Ratio

Dry Brick weight (W1) is immersed in water for 16 hours then weight is again taken (W2)

∴ Absorption ratio = (W2-W1)

• Absorption ratio for 1st class brick should not be more than 20%.
• Absorption ratio for 2nd class brick should not be more than 22.5%.
• Absorption ratio for 3rd class brick should not be more than 25%.

Brick Kiln types

(i) Intermitent kiln

• Up Drought- Movement of gases vertically upward.
• Down Drought- Movement of gases vertically Downward.

(ii) Continous Kiln

• Bull Trench kiln
• Hoffman's kiln
• Tunnel kiln

Brick Masonry