Bricks

Question 1

SILICA

Answer 1

50-60 %
Prevents cracking , shrinking , warping
durability
excess: destroys cohesion and brick becomes brittle

Question 2

ALUMINA

Answer 2

20-30%
cheif constituent of the brick
plasticity
excess: shrink and warp while drying

Question 3

IRON OXIDE

Answer 3

5-6%
red colour
excess: brick dark blue or black

Question 4

LIME

Answer 4

<5%
small quantity
fine powdered
prevents shrinkage
excess: brick to melt ,loose shape

Question 5

MAGNESIA

Answer 5

0.1%
yellow color
decreases shrinkage
excess: decay of brick

Question 6

Chemical compostion of the bricks:

Answer 6

Silica
Alumina
iron oxide
lime
magnesia

Question 7

natural drying of bricks

Answer 7

7-14 days

Question 8

artificial drying method

Answer 8

by oven <48 hrs

Question 9

firing chamber : where dried brick is sent through :

Answer 9

5-10 hrs at 200-900 celcius

Question 10

cool down the bricks for

Answer 10

48-72 hrs

Question 11

in clamps bricks are burnt for

Answer 11

1-2 months and cooled for the same period

Question 12

clamp burning

Answer 12

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

Question 13

kiln burning

Answer 13

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

Question 14

conventional / traditional bricks

Answer 14

230x114x76 mm

Question 15

standard/modular bricks

Answer 15

190x90x90 mm

Question 16

perforated bricks

Answer 16

30-45 %
area<500mm^2
190x90x90 mm
290x90x90 mm
light
less clay
panel walls , partition

Question 17

hollow bricks

Answer 17

not solid , but hollow
thickness not less than 11 mm
any web not less than 8 mm
190x90x90mm
290x90x90mm
290x240x90mm

Question 18

sewer bricks

Answer 18

fire clay 25-45% alumina
190x90x90mm
190x90x40mm
min avg strength 17.5 N/mm^2
water absorbtion <10%

Question 19

water absorbtion

Answer 19

<20%
and first class bricks <15%

Question 20

thermal conductivity

Answer 20

low , so that in summer its colder and winter its warmer

Question 21

sound insulation

Answer 21

heavy poor insulators

Question 22

parts of a brick

Answer 22

streacher long
header shorter side