Being a civil engineer, you should never compromise on the quality of the bricks for construction. Always ensure good quality materials for the construction. Bricks are the oldest and important construction materials because of their durability, reliability, strength and low cost. Bricks are easily available and manufactured at large scales.
As poor quality material indirectly has following consequences:
It
will affect the strength of the structure.
It
will increase the project budget.
It
will lead to wastage of manpower as a result of more reworks.
It will
possess less labour output.
Quality control measures are necessary in civil construction.In this article,I will tell you about how to check the brick quality at the field.
Uniformity
in Size, Shape & Colour
A good brick should have the same size and shape. It
can be a rectangular shape without any bulk on its body.
The surface of the bricks should not be smooth otherwise the mortar will not stick to the brick.
The brick should have uniform color and free of cracks.
It should have a copper color and it can be shiny.
Low-quality bricks not only affect the load carrying
capacity of the wall, but also affect the aesthetic appearance.
The brick size should be 190 mm x 90 mm x 90
mm as per IS specification and weigh about 3 kg.
Reason
for checking - uneven surface and size will require more labour
for shaping the brick before doing brickwork which affects the labor output per
day.
You can to see - Brick calculation for brick masonry rate analysis
 |
Dimensional Accuracy
Quality bricks must have an exact dimension. +/- 3 mm tolerance should
be allowed.
Bricks are the more economical material in construction. If we use low
quality bricks (uneven and heavy), then we have to remove the faults by other
supplementary works (plastering).
To perform this test, select 20 bricks randomly from the brick group and
stack them.Compare them with its length, width, and height. Therefore, if all
bricks are of the same size, then they are eligible for construction.
Soundness
A good brick should give a clear metallic ringing
sound as soon as it hits the second brick.
A good brick must be hard enough, even finger
nails cannot make an impression on its surface.
It should not break when it falls from 1.2 - 1.5
meters above the ground or collides with another brick.
Reason for checking - On site, workers often shift material from one floor to another and sometimes bricks can slip from hand while working. If the brick cannot bear that fall then the bricks dissipate.
Crushing Strength or Compressive Strength Test on
Bricks
The crushing strength of the bricks is determined by placing the bricks in a compression testing machine. After placing the brick in a compression test machine, apply the load on it until the brick is broken. Note the value of the failure load and find the crushing strength of the brick. The minimum crushing strength of brick is 3.50 N/m㎡.
If It is less than 3.50 N/m㎡ , so it is not useful and safe for construction purposes.
Water Absorption
When the brick remains submerged in water for
24 hours, the brick should not absorb more than 20% of its weight.
• Dry
weight (W1) of brick is noted first
• Dip
the brick in water for 24 hours, then weigh it (W2).
Now the percentage of water absorption :
Efflorescence
If you see lots of white patches on the
surface of brick (known as efflorescence)
then the brick should be avoided. This is because bricks have high sodium and
potassium salts
• Immerse a brick in water for 24 hours.
• After 24 hours take out the brick,if white
deposits cover more than 20% of its surface then avoid the brick
Reason for checking- Efflorescence means bricks contain more harmful salts which dissolve in the mortar water and cause the brick structure to collapse.
Bricks should be free of harmful salts (sodium and potassium). If we use this type of bricks in construction, then the salt present in the bricks dissolves with water and causes structural damage.
If you are not sure about the defects, you can
do laboratory tests as per IS 3495 – 1992.
Brick is only used if the extent of efflorescence is from slight to moderate.
Frog
Impression on brick
The brick should have frog impression which increases the
bond strength with mortar.
Check the size of the frog and it should be 100 mm x 40
mm x 10 mm. Any other reduced size of the frog leads to improper motor filling
and a greater amount of mortar is required if the dim.
Durability
A good brick must resist temperatures up to 1200 ° C
rain, frost action and fire effects. The life and durablility of the wall
depends on the good quality of bricks.
Post a Comment