Brick Ass
Brick Ass
Brick Ass
4. List the factors which influence the selection of brick for a project
explain how does absorption affect the selection of brick
6. What is the suitable other way when the brick will shortage in our
area and explain your answer clearly
01. State the harmful ingredients in brick clay
1. LIME
A small quantity of lime is required in brick earth. But if present in excess, it
causes the brick to melt and hence brick looses its shape.
If lime is present in the form of lumps, then it is converted into quick lime
after burning. This quick lime slakes and expands in presence of moisture,
causing splitting of bricks into pieces.
2. IRON PYRITES
The presence of iron pyrites in brick earth causes the brick to get crystallized
and disintegrated during burning, because of the oxidation of the iron pyrits.
3. ALKALIS
These are exist in the brick earth in the form of soda and potash. It acts as a
flux in the kiln during burning and it causes bricks to fuse, twist and warp.
Because of this, bricks are melted and they loose their shape.
The alkalis remaining in bricks will absorb moisture from the atmosphere,
when bricks are used in masonry. With the passage of time, the moisture
gets evaporated leaving grey or white deposits on the wall surface (known as
efflorescence). This white patch affects the appearance of the building
structure.
Efflorescence in Brick
4. PEBBLES
Stone in Brick
Hand moulding
Machine moulding
For hand moulding the tempered clay is forced in the mould in such a way that it
fills all the corners of the mould. Extra clay is removed either by wooden strike or
frame with wire. Mould is then lifted up and raw brick is left on ground.
Machine moulding is is used where large numbers of bricks are to be made.
Machines used for moulding is generally of two types.
In plastic clay machine the clay in plastic state is forced to rectangular openings of
a size equal to the length and breadth of the bricks and are then cut into strips of
thickness of the brick with wires in frames.
In dry clay machines, dry clay is reduced to powder, filled dry into mould by the
machine and then are subjected to high pressure to form hard and well shaped
bricks.
3. DRYING OF BRICKS
Drying is usually done by placing the bricks in sheds with open sides so as to
ensure free circulation of air and protection from bad weather and rains. The bricks
are allowed to dry till they are left with 5 to 7 percent moisture content. The drying
period usually varies from 7 to 14days. The moulded bricks are dried because of
the following reasons.
If damp bricks or green bricks are directly taken to burning then, they are
likely to be cracked and distorted
To remove maximum moisture from the brick so as to save time and fuel
during burning
To increase the strength of raw bricks so that they can be handled and
stacked in greater heights in the kiln for burning without damage.
4. BURNING OF THE BRICKS
It is the very important step in manufacture of bricks. Bricks may be burnt by two
distinct methods given below.
In clamps, one batch of green bricks is heaped along with firewood, coal etc. and
sealed with clay. It is then fired slowly to intense heat which may take many days.
Modern kilns, however, permanent structures consisting of many chambers. There
are intermittent and continuous kilns. Moulded clay is stacked in the chambers.
They are then slowly dried and burned to high temperature and cooled. One cycle
of loading, drying, burning, cooling and emptying may take as much as two weeks.
These processes are carried out intermittently in intermittent kilns and in cyclic
order in continuous kilns.
03.Why is drying of bricks an extremely important operation of the
manufacturing process.
Aesthetics
The use of brick as a building material dates back centuries. Because of brick's
enduring qualities and limitless appearances, designers can satisfy their creative
styles with brick. Brick is readily available in many sizes, colors, textures and
shapes. These can be adapted to achieve virtually any desired style or expression.
A variety of common brick sizes are shown in Figure 1. Brick's small module can
be related to the scale of the wall. These sizes can be combined in such a way as to
create different appearances and patterns. Not only does brick size influence scale
and appearance, but the size of brick influences wall cost because larger units
require fewer brick, normally resulting in less labor. When specifying the size of
units, dimensions should be listed in the following order: thickness (width) by
height by length. Brick manufacturers also offer a wide variety of colors to choose
from. Units whose colors range from reds and burgundies to whites and buffs are
manufactured today. Many manufacturers produce over 100 colors. Many of these
color variations are created during the firing process. Temperature variations and
the order in which the units are stacked in the kiln determine shades of light and
dark. Ceramic glazes, slurries or sand coatings can be applied to the surface to
achieve colors not possible with some clays. The possibilities of using units of
contrasting colors in bands or other patterns are endless. Sample panels, or
mockups, can aid in selecting the desired color by showing the finished,
appearance. Another aesthetic feature to consider when selecting brick is the
texture. Textures on brick can be smooth, wirecut (velour), stippled, tumbled,
brushed, rolled, and more. The texture interacts with light and creates differing and
interestingshadows. Unique design features can easily be achieved by using special
brick shapes. Brick can be molded and formed into any shape, from simple sloped
sill shapes to fancy watertable brick. For most manufacturers, molded shapes are
easier to produce than extruded shapes, because the molded, or soft-mud process is
more adaptable to making brick shapes than the extruded process. Making very
large shapes can be difficult in either process because of problems with proper
drying and firing.
Physical Properties
There are many physical properties which may influence the selection of brick.
Some of these include durability, absorption, compressive strength and abrasion
resistance. This Technical Notes will provide a basic understanding of these
properties to aid in selection of the proper brick. Physical properties required for
proper performance are given in the appropriate American Society for Testing and
Materials (ASTM) specification for brick.
Durability. Currently, there are two accepted methods for demonstrating durability
under ASTM standards: 1) durability as predicted by compressive strength,
absorption, and saturation coefficient, or 2) durability as determined by
compressive strength and passing 50 cycles of the freeze and thaw test. Criteria in
each ASTM specification determine grade or class designations. Because of the
varying climates and applications of brick, specific physical properties are
Required. Brick are classified into these grades or classes according to their
resistance to freezing when wet. Table 1 gives the recommended grade of facing,
building and hollow brick, based on weathering index and exposure. Most
manufacturers make brick to meet the designation for the most severe weathering
exposure, SW or SX, so they may ship brick to all parts of the country. Some
manufacturers produce brick complying only with the designation for moderate
weathering, MW or MX. Grade NW or NX brick are typically confined to interior
applications, or where they are protected from water absorption and freezing. Brick
manufacturers can furnish certification that their product will meet a certain grade
or class.
Application
A building must perform the functions for which it is designed. The materials
selected for a project must also perform as intended. The designer must consider
all factors which a wall or material must withstand. Some of the more important
factors include moisture penetration, temperature variations and structural loads.
No one standard assembly is suitable for all localities, occupancies, or designs;
therefore, the designer must evaluate each factor and its relative effect on the
selection of a material or assembly.
Moisture Penetration. The use of quality materials and workmanship is essential
in obtaining a satisfactory degree of water resistance. When water passes through
brick masonry walls, it invariably does so through separations or cracks
between the brick units and the mortar. It is virtually impossible for significant
amounts of water to pass directly through a brick unit. Therefore, brick units which
develop a complete bond with mortar offer the best moisture resistance. Brick
and mortar properties should be compared to provide compatible materials which
result in more watertight walls. Currently, there are no requirements for the degree
of water resistance of a wall.
Structural Loads. Ability to withstand either gravity or lateral loads relies heavily
on brick strength, mortar strength and dimensions of the wall assembly.
Compressive strength requirements found in the ASTM specifications for brick are
based on durability performance. Structural analysis may require a higher
compressive strength in order to resist the applied loads. Compressive strength of
masonry may be a governing criterion in loadbearing or reinforced brickmasonry
projects.
Cost
Material selection is often based on cost, usually initial cost only. Although initial
cost is important, lifecycle cost is a better tool for making critical decisions. When
deciding between different materials, all costs involved including labor and
maintenance costs, future value and life expectancy should be considered.
The selling price of brick is governed by many factors, including manufacturing
methods and appearance of the unit. When considering different brick, one must
take into account shipping costs. Since most prices quoted are plant prices,
distance between the manufacturing plant and the jobsite is a major determinant of
these shipping costs. Brick manufacturers and distributors can supply brick prices
and shipping prices. Brick price is only one part of the in-place costs. Labor and
overhead costs are approximately twice the brick and mortar costs. Many of the
Masonry Institutes throughout the country provide cost comparisons between
different materials.
Availability
The availability of brick fluctuates with the time of the year and current
construction trends and demands. On the average, brick production time runs about
5 days, from pugging of the clay to the finished, fired product. This can change
depending on many factors such as variations in raw materials, forming process,
and kiln types. Many brick manufacturers have stockpiles of brick, but usually
only a small quantity of each brick type. This may satisfy smaller jobs, but for
large projects requiring large quantities of brick, a special production run must be
made for the job. Most manufacturers have a set schedule as to when they produce
a certain brick shade. It is at this time that the size of the run will be increased to
accommodate the large order. It is wise to determine the brick's availability from
the manufacturer.
06.What is the suitable other way when the brick will shortage in
our area and explain your answer clearly?
a.we can use concrete block instead of bricks:- It made from a mixture of
Portland cement, blended cement, various type of aggregates and water also retread
to as concrete masonry units . it is inexpensive, light weight, durable, easy to
install, fire proof, low maintenance and could be ornamented.
b. calcium silicate brick:- These bricks are also called sand lime and sometimes
flint lime bricks. These are made from fully selected clean sand and /or crust lined
mixed with control quantities of lime and water. These bricks are very accurate in
size and shape but do not have the individual character of clay bricks. these are
strong and homogenous.