1. BRICKS

2. One of the oldest construction material
BRICKS :
One of the oldest construction material
Most popular and leading construction material
REASON:
Low cost
Durable
Light weight
Easy to work with

3. ADVANTAGES OVER STONES:
Light weight
Uniform shape and size
Moulded to required size
Easy laying
Cheaper
Fire resistance
Thinner sections
Less mortar for bonding
Easy transportation
Produced in large quantities

4. RAW MATERIALS: Sl.No. CONSTITUENT % FUNCTION EXCESS QTY. LEADS TO 1
Clay
20 to 30
Plasticity
Shrinkage 2
Sand
50 to 60
Prevents cracking and shrinkage
Brittleness 3
Lime 10
Prevents shrinkage
Helps binding
Swells and disintegrate 4
Iron oxide
4 to 5
Gives red colour
Becomes dark blue 5
Magnesia
Small quantity
Imparts yellow tint and decreases shrinkage
Decay of bricks

5. MANUFACTURE OF BRICKS:
Preparation
Moulding
Drying
Burning

6. PREPARATION:
Upper layer removed ( free from vegetation, gravel and lime)
Clay exposed to atmosphere in wet condition
Clay mixed with ingredients to become homogeneous and attain uniform colour
Clay mix kneaded for moulding

7. MOULDING: Steel or wooden moulds Open both at top and bottom
Prepared according to size of brick
Clay mix filled in the mould, levelled and excess qty. is removed.
Mould is lifted up and the procedure is repeated.

8. DRYING:
Moulded bricks are stacked in layers
Dried for about 6 weeks (depending on weather condition)
BURNING:
Clamps (or) Kilns are used to burn
Stacked and burnt at about 8000 C using coal, firewood etc.
Burning imparts strength and hardness
It should be properly burnt
Over-burnt leads to brittleness
Under-burnt leads to softness and hence less load carrying capacity

9. USES: Walls, Bridges, Dams and Culverts
Pavements, Kerbs Partitions and roads
Fire bricks used for fire resisting structures
Ornamental works
Perforated and hollow bricks for heat insulation
Compound walls, Columns, Stairs and Arches
Broken pieces for weathering courses

10. CLASSIFICATION: BASED ON THE MANUFACTURING PROCESS FIRST CLASS BRICKS
SECOND CLASS BRICKS
THIRD CLASS BRICKS
FOURTH CLASS BRICKS

11. FIRST CLASS BRICKS: Smooth and rectangular
Parallel, sharp and straight edges
Thoroughly burnt with deep red colour
Uniform texture
Water absorption 12% to 15% of its dry weight when immersed in cold water for 24 hrs
Mettallic (or) Ringing sound by striking
Crushing strength not less than 10.5 N/mm2

12. SECOND CLASS BRICKS: THIRD CLASS BRICKS: FOURTH CLASS BRICKS:
Small cracks are allowed
Water absorption 16% to 20%
Crushing strength not less than 7 N/mm2
USES: all masonry works
THIRD CLASS BRICKS:
Under burnt
Soft and light
Dull sound
Water absorption is 25%
USES: Temporary structures
FOURTH CLASS BRICKS:
Over burnt
Bad shape and size
brittle

13. AVERAGE COMPRESSIVE STRENGTH (N/mm2)
BASED ON COMPRESSIVE STRENGTH (AS PER ISI) [ IS ]
CLASS
AVERAGE COMPRESSIVE STRENGTH (N/mm2)
350 35
300 30
250 25
200 20
175
17.5
150 15
125
12.5
100 10 75
7.5 50 5
3.5

14. SIZE AND WEIGHT: 19 cm x 9 cm x 9 cm
20 cm x 10 cm x 10 cm (including mortar)
3 to 3.5 kg

15. QUALITY OF GOOD BRICKS:
Shape and size
Uniform with straight edges
Colour
Deep RED
Texture and Compactness
No fissures and holes
Hardness and Soundness
No finger nail impression
Compressive strength
[ 10.5 N/mm2]
Water absorption
[ Not more than 20%]
Density
[ 17 to 19 kN/m3 ]
Shear strength
5 To 7 N/mm2
Fire Resistance
High
Soluble salts
Free
Breakage
When dropped from 1m height it should not break.

16. TESTS ON BRICKS: IS 3495- 1976 1. COMPRESSIVE STRENGTH
Both faces made smooth
Immersed in water for 24 hrs for three days
The specimen is then placed between the plates of the compression testing machine
Load is applied axially at a uniform rate 14 N/mm2and maximum load at which the specimen fails is noted for determination of compressive strength not less than 3.5 N/mm2
Again immersed in clean water for 3 days
Tested in compression testing machine.
Compressive strength = Load at failure/ Area of the cross section of the brick

17. 2.WATER ABSORPTION TEST:
Dry brick weighed (W1)
Immersed in water for 24 hrs
Again weighed (W2)
Percentage of water absorption = [W2 – W1] W1
X 100

18. 3.EFFLORESCENCE TEST:
Bricks placed in water of 2.5 cm depth till water is absorbed or evaporated
After drying again placed in water
Examined for efflorescence
Efflorescence is classified as follows:
Nil 0%
Slight 10%
Moderate 10 to 50%
Heavy more than 50%

19. Thank You.,
Presented By.,
Aravinth M