Qualities of Good Bricks
The good bricks which are to be used for the construction of important structures should posses the following qualities;
- The bricks should be table-moulded, well burnt in kilns, copper-coloured, free from cracks and with sharp and square edges. The colour should be uniform and bright.
- The bricks should be uniform in shape and should be of standard size.
- The bricks should give a clear metallic ringing sound when struck with each other.
- The bricks when broken or fractured should show a bright homogeneous and uniform compact structure free from voids.
- The brick should not absorbs water more than 20% by weight, for first class bricks and 22% by weight for second class bricks, when soaked in water for a period of 24 hours.
- The bricks should be sufficiently hard. No impression should be left on brick surface, when it is scratched with finger nail.
- The bricks should not break into pieces when dropped flat on hard ground from a height of about one meter.
- The bricks should have low thermal conductivity and they should be sound proof.
- The bricks, when soaked in water for 24 hours, should not show deposits of white salt when allowed to dry in shade.
- No bricks should have the crushing strength below 5.50 N/mm2.