CLASSIFICATION OF BRICKS

2. • Moulding of Bricks
• Bricks are made in metric sizes called modular bricks, as prescribed by the Bureau of Indian
Standards. Nominal size of the bricks is 20cm X 10cm X 10cm, which include the thickness of the
mortar and the actual size of modular brick is 19cm X 9cm X 9cm.
• Hand Moulding
• Ground Moulding:
• Table Moulding
• Machine Moulding
• Plastic Method:
• Dry Method:
• Drying of Bricks

3. • Burning of Bricks
• After the process of moulding and drying, bricks are burnt in kilns to
impart hardness, strength and to increase the density of the brick. Some
physical and chemical changes take place in the burning of bricks. Heating
brick to about 640°C produces only physical changes. If a brick is heated
up to 700-1,000°C, it undergoes chemical changes. During this reaction,
the materials present in brick alumina and silica fuse together to make the
brick strong and stable to prevent from cracking and crumbling.
• Clamp or Open Kiln
• Intermittent Kiln:
• Continuous Kilns:

4. Qualities of good bricks
• The good bricks which are to be used for the construction of important structures should posses the following qualities:
• The bricks should be table-mounted, well burnt in kilns, copper-coloured, free from cracks and with sharp & square edges. The
colour should be uniform and bright.
• The bricks should be uniform in shape and should be of standard size.
• The bricks should give a clear metallic ringing sound when struck with each other.
• The bricks when broken or fractured should show a bright homogeneous and uniform compact structure free from voids.
• The bricks shouldn’t absorb water more than 20 percent by weight for first class bricks and 22 percent by weight for second class
bricks, when soaked in cold water for a period of 24 hours.
• The bricks should be sufficiently hard. No impression should be left on brick surface, when it is scratched with finger nail.
• The bricks should not break into pieces when dropped flat on hard ground from a height of about one meter.
• The bricks should have low thermal conductivity and they should be sound-proof.
• The bricks, when soaked in water for 24 hours, should not show deposits of white salts when allowed to dry in shade.
• No brick should have the crushing strength below 5.5 N/mm2.

5. CLASSIFICATION OF BRICKS
• Sun-dried or Kacha Bricks
• Burns or Pucca Bricks
• First Class Bricks
• Second class bricks
• Third class or pilla bricks
• Overburnt or Jhama bricks