BRICK & BRICK MASONRY - Civil Engineering short notes and previous year questions
BRICK
- Standard size / modular size : 19 x 9 x 9 cm
- Nominal size : 20 x 10 x 10
- Non modular / traditional size : 22.9 x 11.2 x 7
- Weight of 1 brick : 3 - 3.5 ( 30 - 35 N )
- Unit weight of brick : 18 KN / m3 / 1800 kg/m3
- Specific gravity of brick : 1.8 - 2
INGREDIENTS OF GOOD BRICK EARTH
I. Alumina
II. Silica
III. Lime
IV. Iron oxide
V. Magnesia
INGREDIENTS OF BRICK
I. ALUMINA ( 20 - 30 % )
• Chief ingredient
• Imparts plasticity to the brick earth
• Excess alumina causes warping and shrinkage
II. SILICA ( 50 - 60 % )
• Major ingredient
• Imparts durability , uniform shape to brick
• Prevents shrinkage and warping
• Excess amount reduces cohesiveness and makes the brick brittle
III. LIME ( should not be greater than 5 % )
• Reduces the fusing temperature of silica from 1730 *c to 350 - 1100 *c
• If excess causes melting of brick , changing shape
• Prevents shrinkage
IV. IRON OXIDE ( 5 - 6 % )
• Imparts red color to the brick
• Helps fuse silica
• If excess makes the brick blackish of dark blue
V. MAGNESIUM ( 1 - 2 % / 2 - 4 % )
• Imparts yellow tint
• If excess results in decaying of brick
HARMFUL INGREDIENTS OF BRICK
I. LIME : Shape loss , melting
II. IRON PIRITES / FOOLS GOLD : crystallization & disintegration due to oxidation of iron pirites
III. LAMINATION : due to presence of entrapped air in clay
IV. PEBBLES : causes improper mixing , makes brick porous
V. VEGETATIVE COVER / ORGANIC MATTER :
• during burning gasses evolve and escapes making the brick porous.
• Emission of gasses by burning of carbonaceous matter is called BLOATING
VI. ALKALYS
• Mainly present in the form of soda & potash
• Absorbs moisture and when evaporate leaves a layer of grey or white deposit - efflorescence
• Gypsum and pirates also causes efflorescence
MANUFACTURE OF BRICKS
- PREPERATION OF CLAY
- MOULDNG
- DRIYING
- BURNING
I. PREPERATION OF CLAY
1. unsoiling : 20 cm depth of top soil is removed
2. digging : soil is digged out and heaps of 0.6 -1.2 m height is formed
3. cleaning : pebbles , vegetative maters are cleaned
4. weathering :
• softening or mellowing of soil
• Exposed to atmosphere in layer of 0.6 - 1.2 m
• Makes the earth moisture content uniform
• Monsoon is preferred
5. blending : ingredients checked, added or removed if needed
6. tempering :
• Makes the soil to the desired plasticity
• Water is added in adequate quantity ‘ mm ‘
i. Pugging : pug mills are used
ii. Kneading : pressed or kneaded under the feet of cattle
III DRYING
• To reduce dampness
• 2 types of moisture present
i. Free moisture : moisture in void , can be removed by drying
CLAMPS
• Temporary structure
• Small scale production
• Cheap , no skilled labor required , economical
• Burning in clamp is called pazhwa
KILN
• Permanent structure
• Burning in kiln is called Bhatta
• Types
i. Intermittent
ii. Continuous
Hoffman kiln
• Overground structure
• Highly efficient
• Most common
• Circular shape , 12 chambers
• Central chimney
• Works throughout the year
Bull trench kiln
• Widely used in India
• Partially underground
• Movable chimney
• 12 chambers
• Elliptical shape
• Cannot work all year
Tunnel kiln
• Bricks move in trollies
• Path moved by trollies is called Crete
way
CLASSIFICATION OF BRICKS
I. BURNT BRICKS / PAKKA BRICKS : classified into 1st class, 2nd class, 3rd class, 4th class bricks
II. UNBURNT BRICKS / KACHA BRICKS : sun dried bricks without burning
BURNT BRICKS classified into :
CLASSIFICATION OF BRICKS
HOLLOW BRICKS
• Aka cellular bricks , cavity bricks
• Weight = 1/3rd weight of standard bricks
• Spacing between cavity - 2 - 3 cm
PAVING BRICKS
• Used in garden
• High iron content
• Water absorption : 5 %
PERFORATED BRICKS
• 30 - 45 % area is perforated
• Compressive strength > 7 N/mm2
• Water absorption should not be greater than 15 %
FIRE BRICK / REFRACTORIES ( 5 - 10 % water absorption )
BRICK MASONRY
I. STRETCHER : brick laid with its length parallel to the direction of wall
II. HEADER : brick laid with its width parallel to the direction of wall
III. ARRISES : edge formed by the intersection of two surfaces (12 nos)
IV. PERPENDS : vertical joint that separate brick with one another
V. LAP : horizontal distance between two vertical joins in successive course (¼ th brick length=5 cm )
VI. BATS : piece of brick cut across the length or along the width
VII.CLOSERS :
• a piece of brick used to close bond at the end
• Provided to stagger vertical joint
• Types :
i. King closer : removing triangular portion joining half width and half length
ii. Queen closer : cut longitudinally at half width
iii. Beveled closer : half width and full length
iv. Mitered closer : full width cut making an angle 45 - 60 with length
VIII.FROG :
• projection of 1 - 2 cm on top face of brick
• acts as a key for mortar
• Stock board or lamin board used to make frog ( palette board if both not in option )
TYPE OF BONDS
1 STRETCHER BOND
• Used for small height
• Half brick thick wall
• Partition walls , parapet walls
2 Header bond
• Used for curved walls
• One brick wall thickness
• Used in arches
3 English bond
• Alternate courses of headers and stretchers
• Alternate headers are placed centrally over stretcher
• No of joints in header course is 2 times the joint in stretcher course
• It is the strongest bond
FLEMISH BOND
• More importance to appearance than strength
• Each cource have alternate headers and stretchers
• All headers placed centrally over the stretchers
• All cources have equal number of joints
• Minimum thickness is 1 ½
• 2 types :
i. Single Flemish : inner face English and outer face Flemish , more strength
ii. Double Flemish : both faces Flemish ( min thickness : 20 cm )
4 GARDEN WALL BOND
• 2 m max height
• Used as compound / garden wall
ENGLISH GARDEN WALL BOND
• One header course after 3 - 5 stretcher courses
• Queen closer after quoin header
• Alternate courses have quoin header
FLEMISH GARDENWALL BOND
• One header after 3 - 5 stretcher in a single course
• ¾ brick bat after quoin header
• All headers placed centrally over stretcher
5 RAKING BOND
DIAGONAL BOND
• Inclined to one side
• Used for flooring and ornamental
works
• 2 - 3 brick wall thick
HERRING BOND
• Inclined to both sides
• Thickness > 4 brick wall thick
• Used for flooring
ZIG ZAG BOND
• Inclined to any direction
• Used for flooring and ornamental
works
6. DUTCH BOND : modified English bond
7. MONK BOND : modified Flemish gardenwall bond
8. SILVER COCKS BOND : aka brick on edge bond, bull header or bull stretcher
9. ST. ANDREWS BOND / ENGLISH CROSSOVER BOND : modified English bond
TOOLS USED IN BRICK MASONRY
I. TROWEL : for placing and spreading , most important tool
II. PLUM BOB : to check verticality
III. STRAIGHT EDGE : to check alignment
IV. MASON SQUARE : to check right angled connections
V. GAUGE ROD : check height of each course
VI. LINE & PIN : to check alignment, easy construction of brickwork
VII. FLOAT : for spreading the mortar
VIII. WOODEN TEMPLATE : to check the inclination of surface of brick
IX. CROW BAR : to pull out nails
X. BOLSTER : large hammer for accurate cutting of brick
XI. SCUTCH : hammer used for cutting brick
XII. BRICK AXE : sharp tool used for cutting brick
XIII. BRICK HAMMER : hammer with one sharp edge and one blunt edge
XIV. FOUR FOLD FOOT RULE : wooden scale having 4 pieces which can be folded into small size
PREVIOUS YEAR REPEATED QUESTIONS BASED ON BRICK AND BRICK MASONRY