Bricks & Its Classification
Brick
is obtained by moulding good clay into a block, which is dried and then burnt.
This is the oldest building block to replace stone. Manufacture of brick
started with hand moulding, sun drying and
burning
in clamps. A considerable amount of technological development has taken place
with better
knowledge
about to properties of raw materials, better machinaries and improved
techniques of moulding
drying
and burning.
The
size of the bricks are 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.
Types of Bricks
Bricks
may be broadly classified as:
(i) Building bricks
(ii) Paving bricks
(iii) Fire bricks
(iv) Special bricks.
(i) Building
Bricks: These bricks are used for the construction of
walls.
(ii) Paving
Bricks: These are vitrified bricks and are used as
pavers.
(iii) Fire Bricks: These bricks are specially made to withstand furnace temperature.
Silica bricks
belong
to this category.
(iv) Special
Bricks: These bricks are different from the commonly
used building bricks with respect to their shape and the purpose for which they
are made. Some of such bricks are listed below:
(a) Specially shaped bricks
(b) Facing bricks
(c) Perforated building bricks
(d) Burnt clay hollow bricks
(e) Sewer bricks
( f ) Acid resistant bricks.
(a) Specially
Shaped Bricks: Bricks of special shapes are manufactured to
meet the
requirements
of different situations.
Bull
nosed brick Cant brick Plinth brick
Channel
brick
Coping
brick Cornice brick
(b) Facing
Bricks: These bricks are used in the outer face of
masonry. Once these bricks are
provided,
plastering is not required. The standard size of these bricks are 190 × 90 ×
90
mm or 190 × 90 × 40 mm.
(c) Perforated
Building Bricks: These bricks are manufactured with area of
perforation of
30
to 45 per cent. The area of each perforation should not exceed 500 mm2. The perforation
should
be uniformly distributed over the surface. They are manufactured in the size
190
×
190 × 90 mm and 290 × 90 × 90 mm.
(d) Burn’t
Clay Hollow Bricks: They are light in
weight. They are used for the construction of partition walls. They provide
good thermal insulation to buildings. They are manufactured in the sizes 190 ×
190 × 90 mm, 290 × 90 × 90 mm and 290 × 140 × 90 mm. The thickness of any shell
should not be less
than
11 mm and that of any web not less than 8 mm.
(e) Sewer Bricks: These bricks are used for the construction of sewage lines. They
are
manufactured
from surface clay, fire clay shale or with the combination of these. They
are
manufactured in the sizes 190 × 90 × 90 mm and 190 × 90 × 40 mm. The average
strength
of these bricks should be a minimum of 17.5 N/mm2 . The water absorption
should
not be more than 10 per cent.
( f ) Acid
Resistant Bricks: These bricks are used
for floorings likely to be subjected to acid
attacks,
lining of chambers in chemical plants, lining of sewers carrying industrial
wastes
etc.
These bricks are made of clay or shale of suitable composition with low lime
and
iron content, flint or
sand and vitrified at high temperature in a ceramic kiln.