Brick is one of
the oldest building material that continues to be a most popular and leading
construction material because of being cheap, durable and easy to handle and
work with. Fly Ash & Clay bricks are used for building-up exterior and
interior walls, partitions, piers, footings and other load bearing structures.
Shape of a brick
is rectangular and its size can be conveniently handled with one hand. Brick
may be made of burnt clay or mixture of sand and lime or of Portland cement
concrete.
Dimensions of a
brick are interrelated as below:
Length of brick
= 2 × width of brick + thickness of mortar
Height of brick
= width of brick
Size of a
standard brick (also known as modular brick) should be 19 × 9 × 9 cm and 19 × 9
× 4 cm.
When placed in
masonry the 19 × 9 × 9 cm brick with mortar becomes 20 × 10 × 10 cm.
Classification
of Bricks
On Filed Practice
Clay bricks are
classified as first class, second class, third class and fourth class based on
their physical and mechanical properties.
First Class
Bricks
1. These are
thoroughly burnt.
2. The surface
should be smooth and rectangular, with parallel, sharp and straight edges and
square corners.
3. These should
be free from flaws, cracks and stones.
4. These should
have uniform texture.
5. No impression
should be left on the brick when a scratch is made by a finger nail.
6. The fractured
surface of the brick should not show lumps of lime.
7. A metallic or
ringing sound should come when two bricks are struck against each other.
8. When immersed
in water, water-absorption should be less than 20%.
9. The crushing
strength of the brick should not be less than 10 N/mm2. This limit
varies with different Government organizations around the country. Uses: First
class bricks are recommended for pointing, exposed face work in masonry structures,
flooring and reinforced brick work.
Second Class Bricks
are
supposed to have the same requirements as the first class ones except that
1. Small cracks
and distortions are permitted.
2. A little
higher water absorption of about 16–20% of its dry weight is allowed.
3. The crushing
strength should not be less than 7.0 N/mm2.
Uses: Second
class bricks are recommended for all important or unimportant hidden masonry
works and cantering of reinforced brick and reinforced cement concrete (RCC)
structures.
Second Class Bricks
are
under burnt. They are soft and light-coloured producing a dull sound when
struck against each other. Water absorption is about 25 per cent of dry weight.
Uses : It is used
for building temporary structures.
Third Class Bricks are over burnt and badly
distorted in shape and size and are brittle in nature.
Uses: The ballast of such bricks
is used for foundation and floors in lime concrete and road metal.
