Bricks Flashcards
SILICA
50-60 %
Prevents cracking , shrinking , warping
durability
excess: destroys cohesion and brick becomes brittle
ALUMINA
20-30%
cheif constituent of the brick
plasticity
excess: shrink and warp while drying
IRON OXIDE
5-6%
red colour
excess: brick dark blue or black
LIME
<5%
small quantity
fine powdered
prevents shrinkage
excess: brick to melt ,loose shape
MAGNESIA
0.1%
yellow color
decreases shrinkage
excess: decay of brick
Chemical compostion of the bricks:
Silica
Alumina
iron oxide
lime
magnesia
natural drying of bricks
7-14 days
artificial drying method
by oven <48 hrs
firing chamber : where dried brick is sent through :
5-10 hrs at 200-900 celcius
cool down the bricks for
48-72 hrs
in clamps bricks are burnt for
1-2 months and cooled for the same period
clamp burning
60% first class
temporary structre
low initial cost
low fuel cost
uneven burning
not large amount of bricks
not in the monsoon season
unregulated firing
long time for burning and cooling 3-4 months
heat wastage
kiln burning
90% first class bricks
permanent structre
firing 24 hrs
cooling 4 days
het of hot gases is utilised
high initial cost
high fuel cost
constant supervision
conventional / traditional bricks
230x114x76 mm
standard/modular bricks
190x90x90 mm
perforated bricks
30-45 %
area<500mm^2
190x90x90 mm
290x90x90 mm
light
less clay
panel walls , partition
hollow bricks
not solid , but hollow
thickness not less than 11 mm
any web not less than 8 mm
190x90x90mm
290x90x90mm
290x240x90mm
sewer bricks
fire clay 25-45% alumina
190x90x90mm
190x90x40mm
min avg strength 17.5 N/mm^2
water absorbtion <10%
water absorbtion
<20%
and first class bricks <15%
thermal conductivity
low , so that in summer its colder and winter its warmer
sound insulation
heavy poor insulators
parts of a brick
streacher long
header shorter side
