Theory
I.S. 1077-1957 gives the
specification of common burnt clay brick. The percentage of water absorption
should not be more than 20 % fora brick having crushing strength below 125
kg/cm2 and 15 % for strength above it. The allowable percentage of
water absorption for roofing tiles and floaring tiles should be as per the
requirements of I.S. 645-1972 and I.S. 1237-1959 replace.
Application
The roofing and flooring tiles
are required to be water repellent to prevent percolation and dampness. Bricks
being porous absorb and hold considerable amount of water. If the prosity is
beyond the permissible limit it leads to the dampness in the walls.
Items required
1. Specimen
of bricks
2. Roofing
tiles
3. Flooring
tiles
4. Water
tank
5. Oven
6. Water
cotton
7. Weighing
balance
8. Standard
weights
Procedure
1. The
given specimen of bricks, roofing tiles and flooring tiles were kept in oven at
1100 until they attached a constant weight.
2. They
were allowed to cool and weighed.
3. They
were submerged in potable water of temperature 150
4. After
24 hours they were removed and their surface was wiped out with waste cotton.
5. Their
final weight after immersion was determined.
Precautions
1. The
specimen were selected by random sampling procedure. Sample were taken from the
top, sides and from the interior of the stack.
2. The
specimen were well dressed before the test.
3. The
bricks were identified by numbers.
Observation table
For bricks = W2 – W1 / W1 x 100 = X %
Type
|
Size
|
Dry wt.
|
Wt. of brick (w2)
|
% of water observed
|
A
|
22x10x5.5
|
1870 gms
|
2870 gms
|
26.24 %
|
B
|
22x10x5.5
|
1840 gms
|
2250 gms
|
22.28 %
|
C
|
21.5x9.5x5.5
|
1755 gms
|
2370 gms
|
35.04
|
For manglore tiles = W2 – W1 / W1 x 100 = X %
Type
|
Size
|
Dry wt.
|
Wt. of brick (w2)
|
% of water observed
|
A
|
3.9x22x2
|
1780
|
2020
|
11.88 %
|
B
|
3.9x22x2
|
1910
|
2205
|
13.88 %
|
C
|
3.9x12x2
|
1790
|
2015
|
11.17 %
|
For flooring tile = W2 – W1 / W1 x 100 = X %
Type
|
Size
|
Dry wt.
|
Wt. of brick (w2)
|
% of water observed
|
A
|
25x25x2.2
|
2836
|
3130
|
10.36 %
|
B
|
25x24x2.23
|
2824
|
3075
|
8.88 %
|
C
|
24x25x2.1
|
2788
|
3010
|
7.96 %
|
Calculation
Percentage of water absorbed
= W2 – W1 / W1 x 100 = X %
Where w1 = dry
weight, w2 = wet weight
= W2 – W1 / W1 x 100 = X %
= 13.48 %
Result
The percentage of water absorption for
flooring tile
1. Tile
no. A = 8.88 %
2. Tile
no. B = 7.96 %
