Classification of Bricks
Unburnt or sun dried bricks
These are dried under sunlight.These are used for temporary and cheap construction.It is also used for filling works.
- First class bricks
- Second class bricks
- Third class bricks
- Fourth class bricks
First Class Bricks
Made of good earth which is free from saline deposits and are sand molded.Burnt thoroughly without being vitrified and have deep red, cherry and copper color.Regular and uniform in shape and size with sharp and square edges and parallel faces.Must be homogeneous in texture and emit a clear ringing sound on being struck together.Free from flaws, cracks, chops, stones and lime.Have a minimum crushing strength of 105 kg per sq. cm when tested according to the test
Second Class Bricks
They shall be well burnt or slightly over burnt.They must give clear ringing sound when struck.The may have slight irregularities in size, shape and color.They may have slight chips, flaws or surface crack but must be free from lime or kankar.The minimum crushing strength of second class brick should be 70 kg per sq cm.
Third Class Bricks
These bricks are slightly under burnt or over burnt.They are not uniform in shape, size and edges.They shall not observe water more than 25% of their own dry weight after 24 hours, immersion in cold water.They have some signs of efflorescence
Fourth Class Bricks
These are over burnt bricks which are dark in colour and are irregular in size and shape.These are used as aggregate in concrete and for flooring.Over burnt bricks are not used for building construction.