Qualities of Good Bricks

Qualities of Good Bricks

 The qualities of good bricks are as listed below:

Colour

Colour should be uniform and bright. Shape          

 Bricks should have plane faces.

 They should have sharp and truly right angled corners.

Texture

Bricks should have fine, dense and uniform texture.

 A fractured surface should not show fissures, cavities, loose grit and unborn lime.

Size  

Bricks should be of standard size as prescribed by the standard code.

 Soundness

 Bricks should give a metallic sound when struck with a hammer or with another brick.

Strength

Crushing strength of bricks should be as high as possible. The Indian Standard code does not permit the use of any brick with crushing strength of less than 55kg/cm2. A field test for strength is that when dropped flat from a height of 0.9m to 1m on a hard ground, the brick should not break into pieces

Water absorption

 After immersing bricks in cold water for 24 hours, water absorption of bricks should not be more than 20 per cent by weight. For class-I work; this limit is 15 per cent.

 Efflorescence

 Bricks should not show white patches when soaked in water for 24 hours and then allowed to dry in shade. White patches are due to the presence of sulphates of calcium, magnesium, sodium and potassium, and they keep the masonry permanently in a damp and wet condition.

Thermal conductivity

Bricks should have low thermal conductivity so that buildings built with them are cool in summer and warm in winter. 

Sound insulation

Heavier bricks are poor insulators of sound while light weight and hollow bricks provide good sound insulation. The strength and sound insulation properties of bricks contradict each other. Hence, bricks with unnecessarily too high strength (heavy bricks) need not be used.       

Fire resistance

Fire resistance of bricks is usually good. In fact sometimes bricks are used to encase steel columns as a measure of fire protection.