Types of Bricks
There are different types of bricks available on the
market used for various kinds of purposes. These bricks can be categorized
under various headings and subheadings on different basis. The various
classifications of types of bricks are briefly discussed below.
Classification based on method of manufacturing
Bricks can broadly be categorized into two types as
follows on the basis of how its manufactured:
·
Unburnt or sun-dried bricks
·
Burnt bricks
o
Unburnt bricks
Unburnt bricks or sun-dried bricks
are the types which are dried with the help of heat received from sun after the
process of moulding. These bricks can only be used in the construction of
temporary and cheap structures. Such bricks should not be used at places
exposed to heavy rains.
o
Burnt Bricks
Burnt bricks are prepared by burning
the brick-mould in the kiln inside the factory. These are the most commonly
used bricks for construction works. They can be further classified into
following four categories:
1. First
class bricks
These bricks are table-moulded and of
standard shape and they are burnt in kilns. The surfaces and edges of the
bricks are sharp, square, smooth and straight. They comply with all the
qualities of good bricks. These bricks are used for superior work of permanent
nature.
2. Second
class brick
These bricks are ground-moulded and
they are burnt in kilns. The surface of these bricks is somewhat rough and
shape is also slightly irregular. These bricks may have hair cracks and their
edges may not be sharp and uniform. These bricks are commonly used at places
where brickwork is to be provided with a coat of plaster.
3. Third
class bricks
These bricks are ground-moulded and
they are moulded in kilns. These bricks are not hard and they have rough
surfaces with irregular and distorted edges. These bricks give dull sound when
struck together. They are used for unimportant and temporary structures and at
places where rainfall is not heavy.
4. Fourth
class bricks
These are over-burnt type of brick
with irregular shape and dark colour. These bricks are used as aggregate for
concrete in foundations, floors, roads, etc. because of the fact that the
over-burnt bricks have a compact structure and hence they are sometimes found
to be stronger than even the first class bricks.
Classification
based on shape
The ordinary bricks are rectangular solids. But
sometimes the bricks are given different shapes to make them suitable for
particular type of construction. Here we have enlisted different types of
bricks available with various shapes:
·
Bullnose
brick: A brick molded with a rounded angle is termed as a
bullnose. This type of brick is used for a rounded quoin. A connection which is
formed when a wall takes a turn is known as quoin. The center of the curved
position is situated on the long center-line of brick.
·
Channel
bricks: These types of bricks are molded to the shape of a
gutter or a channel and they are often glazed. These bricks are used to
function as drains.
·
Coping
bricks: These bricks are made to suit the thickness of walls
on which coping is to be provided. Such bricks take various forms such as
chamfered, half round or saddle-back.
·
Cownose
bricks: A brick moulded with a double bullnose on end is
known as a cownose.
·
Curved
sector bricks: These bricks are in the form of curved
sector and they are used in the construction of circular brick masonry pillar,
brick chimneys, etc.
·
Hollow
bricks: These are also known as the cellular or cavity
bricks. Such bricks have wall thickness of about 20mm to 25mm. They are
prepared from special homogeneous clay. They are light in weight about
one-third the weight of the ordinary brick of the same size. These types of
bricks can be laid almost about four times as fast as the ordinary bricks and
thus the use of such bricks leads to speedy construction. They also reduce the
transmission of heat, sound and damp. They are used in the construction of
partitioning.
·
Paving
bricks: These bricks are prepared from clay containing a
higher percentage of iron. The excess iron vitrifies the bricks at a low
temperature. Such bricks resist better the abrasive action of traffic. The
paving bricks may be plain or chequered. These bricks are extensively used for
garden walks, street pavements, stable floors, etc. These types of bricks also
render the floor less slippery.
·
Perforated
bricks: These bricks contain cylindrical holes throughout
their thickness. These bricks are light in weight and they require less
quantity of clay for their preparation. The drying and burning of these bricks
are also easy. If perforated bricks of large size are used, it will result in
the increase of output of mason. The perorated bricks are used in the
construction of panels for lightweight structures and multi-storeyed framed
structures. They may be circular, square rectangular or any other regular shape
in cross-section. The distance between the side of brick and edge of
perforation should not be less than 15mm. The distance between the edges of
successive perforations should preferably be not less than 10mm. The water
absorption after immersion for 24 hours in water should not exceed 15 percent
by weight. The compressive strength of perforated bricks should not be less
than 7 N/mm2 on gross area.
·
Purpose-made
bricks: In order to achieve certain purpose, these types of
bricks are made. The splay or cant bricks are made for jambs of doors and
windows. The arch bricks are made of wedge shape to keep mortar joint of
uniform thickness. The ornamental bricks are prepared for corbels, cornices,
etc. Similarly, engineering bricks are prepared for constructions where high
durability, compression strength and adequate resistance to sudden shocks are
required. These types of bricks are usually more costly than the ordinary
bricks. But they grant safe, clean and quick construction. Hence, their cost is
justified by their excellent performance in situation for which they are
purposely prepared.
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