Types and properties of bricks
Bricks is produced from well clay molding, that is dried and then burnt. The size of the brick varies from 90 mm ? 90 mm ? 90 mm and 190 mm ? 90 mm ? 40 mm. With mortar joints, the size of brick varies from 200 mm ? 100 mm ? 100 mm and 200 mm ? 100 mm ? 50 mm.
Types of Bricks: Bricks are categorized as -
(i) Building bricks, (ii) Paving bricks, (iii) Fire bricks, (iv) Special bricks.
Properties of Bricks: The standard quality bricks should contain the following properties -
(i) Colour: The color should have been identical and clear.
(ii) Shape: Shape of the bricks should have been sharp and genuine rectangular angles.
(iii) Size: There should be standard dimensions for bricks with adherence to codes.
(iv) Texture: A standard brick should contain a fine, solid and consistent texture. They should be free from fissures, cavities, loose grit and unburned lime.
(v) Virtue: If the brick is hit with another brick, there should be a metal sound.
(vi) Hardness: If scratches are made with finger on a brick, there should not be any mark on the brick.
(vii) Strength: The breaking strength of brick should not be under 3.5 N / mm2. A field test is conducted to check the strength by dropping the brick from a height of 0.9 m to 1.0 mm on a hard surface. If the brick has good strength, the stone should not be broken into pieces.
(viii) Water absorption: Once the brick is drowned in water for 24 hours, the water absorption rate should not exceed 20 percent by weight. For class I bricks, this limit remains 15 percent.
(ix) Efficiency: There should not be any white patches in bricks when they are drenched in water for 24 hours and then allowed to dry in the shade. White stains may appear because of the existence of sulfate of calcium, magnesium and potassium. They retain masonry in wet and humid conditions.
(x) Thermal conductivity: Bricks should contain low thermal conductivity, so the buildings developed with bricks should have cold temperature in summer and warm temperature in winter.
(xi) Sound insulation: Bigger bricks have poor sound insulators whereas light and hollow bricks have superior sound insulation.
(xii) Fire resistance: Normally, the fire resistance capacity of brick is good. Actually, bricks are utilized to trap steel columns to safeguard them from fire.