Properties of a Good Brick
A brick is
said to be good quality if it satisfies following conditions
- Colour: A good brick must have uniform & bright colour.
- Shape: Bricks should have sharp and true right angled corners. They should have plane faces.
- Texture: They should not possess fissures, cavities, unburnt lime & loose grit. They should possess fine, dense and uniform texture.
- Size: Bricks should be of standard sizes as prescribed by codes.
The size of
the brick is of 90 mm × 90 mm × 90 mm and 190 mm × 90 mm × 40 mm.
With mortar
joints, the size of these bricks are taken as 200 mm × 100 mm × 100 mm and
200 mm × 100
mm × 50 mm.
- Strength: Crushing strength of brick should never be less than 3.5 MPa. A field test for strength is that when a brick is dropped from a height of 0.9 m to 1.0 m on to the hard ground, it should not break into pieces.
- Soundness: When struck by the hammer or by another brick, it should generate a metallic or ringing sound.
- Hardness: The brick should not show any impression when scratched on its surface using fingers.
- Water Absorption: After immersing the brick in water for 16 hours, water absorption should not be more than
· 20
% by weight for first class bricks
· 22.5
% for second class bricks
· 25%
for third class bricks
- Efflorescence: Bricks when soaked in water for 24 hours, it should not show deposits of white salts when allowed to dry in shade. White patches are due to the presence of sulphate of calcium, magnesium and potassium. They keep the masonry permanently in damp and wet conditions.
- Thermal Conductivity: Bricks should have low thermal conductivity, so that buildings built with them keep it warm in winter & cool in summer.
- Fire Resistance: Fire resistance of bricks is usually good. Hence bricks are sometimes used to encase steel columns in order to protect them from fire.
- Sound Insulation: Light weight and hollow bricks are good sound insulators. While heavier bricks are poor insulators of sound.
No comments:
Post a Comment