Download - Bricks as building materiaL-2
Introduction
• Brick is one of the oldest buildingmaterial.
• Extensively used in present time as aleading building material because ofits durability, strength, reliability, lowcost and easy availability.
• Great wall of china was built with bothburnt and dried bricks.
• Bricks and mortar is one of theessential components of brickmasonry.y
• Principal Ingredient:– Alumina: Should contain 20 to 30 %Alumina: Should contain 20 to 30 % ,
Imparts plasticityif present in excess raw bricks shrink and deforms during drying
and burning and becomes very hard on burning. – Silica: Should contain 50 to 60 % ,
Imparts uniform shape to the bricksprevents Cracking, shrinking, and deform of raw bricks.Excess destroys the cohesion between particles and brick becomes brittle
– Lime: Should not exceed 5%Lime: Should not exceed 5%Prevents shrinkage of raw bricks.excess Causes bricks to melt and hence the shape is lost.
– Oxide Of Iron: Desirable Quantity about 5 to 6 percentImparts Red Color to the Brick.Excess makes brick dark blue or blackish and lesser quantity makes itExcess makes brick dark blue or blackish and lesser quantity makes it
yellowish– Magnesia: imparts yellow tint and decreases shrinkage.
E l d h d f b i kExcess leads to the decay of bricks.
Harmful Ingredients in bricks g
– Lime- excess causes bricks to melt and shape is lost
I it b i k t lli d d di i t t d d i b i– Iron pyrites- bricks are crystallized and disintegrated during burning
because of the oxidation of iron pirates.
– Alkalis – mainly found in the form of soda potash. Acts as a flux in the
kiln during burning and they cause brick to fuse, twist and deform.
– Pebbles - it will not allow the clay to be mixed uniformly and thoroughly
which will result into weak and porous bricks.
– Vegetation and organic matters – if doesn’t get burnt completely
causes pores in the brick
Manufacturing of bricksgCriteria for the selection of a brick field• Linked up with the roadLinked up with the road• Situated on the plain ground• Good earth is readily available• It should offer all the facilities to the workers.
Four distinct operationsFour distinct operations– Preparation of clay– Moulding– Drying– Burning
1. Preparation of clay
• The clay for bricks is prepared in
the following order:
a) Un-soiling
b) Digging
c) Cleaning
d) Weathering
e) Blending) g
f) Tempering
2. Moulding• Hand Moulding
– Ground moulded bricks– Table moulded bricks
• Machine Moulding– Plastic clay machinesPlastic clay machines– Dry Clay machines
3. Dryingy g• If the damp bricks are directly burnt, there is a possibility of being cracked
and distorted.• Hence bricks are dried before burning stage artificially or naturally.• Laid longitudinally in stacks.• They are laid along and across the stack in alternate layersThey are laid along and across the stack in alternate layers.• They are kept for drying till 2% of moisture is removed – bone dry• Important fact to be remembered regarding drying of bricks.
A tifi i l D i i th f f t l h t fl d– Artificial Drying: in the form of tunnels or hot floor dryers– Circulation of air– Drying-yardy g y– Period for drying– screens
4. Burningg• Very important stage in the
manufacturing of bricks.I t h d d t th t th• Imparts hardness and strength to thebricks.
• It makes the bricks dense and durableIf b t th b i k ill b• If over burnt, then bricks will becomebrittle.
• If under burnt, they will be soft and willnot be able to take loadnot be able to take load
• Burning is done in:-– Clamps
Kil– Kilns
Definitions
• Arrises Frog
– The edges formed by theintersection of planesurfaces of a brick arecalled arrises.
• FrogTh d i id d– The depression providedin the face of a brickduring its manufacturing
Courses
g gis called the frog.
• Courseeach hori ontal la er of
Arises
each horizontal layer ofbricks laid in mortar iscalled course.
Definitions
• QuoinsQuoins– The external corners of a
wall are called Quoins. AndPerpends
a a e ca ed Quo s dthe bricks forming quoins arecalled quoin bricks. E.g quoinh d i t t hheader or quoin stretcher.
P d
Quoin
HeaderQuoin Stretcher
• Perpends– The imaginary vertical lines
which includes vertical jointswhich includes vertical jointsare called Perpends.
DefinitionsDefinitions
H d• Header– Brick laid with its width in elevation is called
h d I i hi h ll b i k h dheader. In a course in which all bricks are headeris called heading or header course.
• Stretcher– Brick laid with its length in elevation is called
stretcher. In a course in which all bricks areh i ll d h histretcher is called stretcher or stretching course.
Definitions
• Closure– Closure bricks are prepared by cutting standard
brick across length or in different ways to fulfillbrick across length or in different ways to fulfillthe requirements of bond in straight walls,corners, junctions or crosses is called closures.
They are of four typesQ l– Queen closure
– King closure– Bevelled closure
Mitered closure– Mitered closure
• Brick batsBrick bats are prepared by cutting standard brick– Brick bats are prepared by cutting standard brickacross width.
They are of four types– Three quarter batThree quarter bat– Half or square bat– Quarter bat– Bevelled bat
DefinitionsDefinitions
• FacingFacing– The external face of wall is called facing.
• Backing• Backing– The unexposed or internal face of wall is called
backingbacking.• Hearting
Th i t i ti b t f i d b ki i– The interior portion between facing and backing iscalled hearting.
Definitions
• RevealsIt is the verticle sides of door or window opening– It is the verticle sides of door or window openingfrom outside is called reveals.
• Jambs– It is the verticle sides of door or window opening
from inside is called jambs.S ffit• Soffit– The under surface of a lintel is called Soffit. It’s
the horizontal surfacethe horizontal surface.• Sill
– The horizontal surface at the bottom side of aThe horizontal surface at the bottom side of adoor or window opening is called sill.
Definitions
• Column– The isolated vertical load bearing member whose cross sectional
dimensions are much lesser then its length is called column.• Pillar
The isolated vertical non load bearing member used for– The isolated vertical non load bearing member used forornamental purpose or as memorial is called pillar.
• Pier– The isolated vertical load bearing members used as an
intermediate support of a series of arches is called pier.• PilasterPilaster
– The thickened vertical load bearing member strengthening a wallis called pilaster.
St hi• Stanchion– The vertical load bearing member constructed of rolled steel
section is called stanchion.
Definitions
• Mortar– The mixture of binding material and fine aggregate forming a workable paste is
called mortar.
• Grout or slurryy– The thin paste of cement is called grout or slurry. It is used to fill the joints.
• LintelA ll h i t l b t ll i i ll d li t l– A small horizontal member to span up small opening is called lintel.
• Copping– It is provided at the top of a wall to avoid dampness.It is provided at the top of a wall to avoid dampness.
Qualities Of Good Brick• Should be :
– Table moulded– Well burnt in kilns– Copper coloured– Free from cracks– Sharp and square edges
• Uniform in shape and of standard size• Should give clear metallic ringing soundShould give clear metallic ringing sound• Should show a bright homogeneous and uniform compact structure free
from voids• Should not absorb water more than 20 22 % by weight for first class and• Should not absorb water more than 20 – 22 % by weight for first class and
second class brick• Sufficiently hard- no impression should be left