DEFECTS OF BRICKS

  • 1. Over - burning of bricks 
  • If the bricks are overburnt, a soft molten mass is produced and the bricks losses their shape . Such Bricks are not used for construction works.

2 . Under - burning of bricks

  • When brick are not burnt property, the clay is not softened because of insufficient heat and the pores are not closed .
  • This results in higher degree of water absorption and less compressive strength 
  • Such bricks are not recommended for construction works 
3. Bloating 
  • This defect is observed as spongy swollen mass over the surface of burned bricks. 
  • It is caused due to the presence of excess carbonaceous matter and sulphur in brick - clay 
4. Efforescence
  • This is caused because of alkalies present in Bricks .
  • When bricks come in contact with moisture , water is absorbed and the alkalies cry stalise.
  • After drying grey or white powder patches appear on the bricks surface .this can be reduced by selecting proper clay materials for brick manufacturing , preventing moisture to come in contact with the masonry , by providing waterproof coping and by using water repellent materials in morter and by providing damp proof course.
5 . Black core
  • When brick - clay contains bituminous matter or carbon and they are not completely removed by oxidation , the brick results in black core mainly because of improper burning 
6. Chuffs 
  • Deformation of the shape of bricks caused by the rain water falling on hot bricks is known as chuffs 
7 . Checks or cracks 
  • This is because of lumps of lime or excess of water 
  • In case of lime , when bricks come in contact with water , the abserbed water reacts with lime nodules causing expansion and a consequent disintegration of bricks , whereas shrinkage and burning cracks result when excess of water is added during brick manufacturing
8 . Spots 
  • If sulphide , is present in the brick clay , it cause dark surface spots on the brick surfaces . Such Bricks are not only harmful but also unsuitable for exposed masonry work 
9. Laminations 
  • It is by the entrapped air in the voids of clay . Laminations produce thin lamina on the brick faces which weather out on exposure 
  • Such Bricks are weak in structure 
10. Blisters 
  • Broken blisters are generally caused on the surface of sewer pipes and drain tiles due to air imprisoned during their moulding

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