Different properties of Good bricks.

Properties of good bricks:

The following are the required properties of good bricks:

1)Color: Color of bricks should be uniform and bright.

2)Shape: Bricks should have plane faces. They should have keen and  right angled corners.

3)Size: Bricks should be of standard sizes as prescribed by codes.The IS code states that  the brick size shall be 190 mm X 90 mm X 90 mm and with mortar thickness 200 mm X 100 mm X 100 mm.

4)Texture: They should possess fine, dense and uniform texture. They should not possess fissures, cavities, loose grit and UN burnt lime.

5)Soundness: When struck with hammer or with another brick, it should produce metallic sound.

6)Hardness: When brick is scratched with finger nail it should not produce any impression on the brick.

7)Strength: Crushing strength of brick should not be less than 3.5 N/mm 2. A field test for strength is that when dropped from a height of 0.9 m to 1.0 mm on a hard ground, the brick should not break into pieces.

8)Water Absorption: After immersing the brick in water for 24 hours, water absorption should not be more than 20 per cent by its dry weight. For class-I works this limit is 15 per cent.

9) 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 Sulphate of calcium, magnesium and potassium. They keep the masonry permanently in damp and wet conditions.

10) Thermal Conductivity: Bricks should have low thermal conductivity, so that buildings built with them are cool in summer and warm in winter.

11) Sound Insulation: Heavier bricks are poor insulators of sound while light weight and hollow bricks provide good sound insulation.

12) Fire Resistance: Fire resistance of bricks is usually good. In fact bricks are used to encase steel columns to protect them from fire.