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