To determine the Efflorescence of a Burnt Clay Brick by Efflorescence test.
IMPORTANCE OF PRACTICAL:
Bricks are the major requirement for constructing a building and are a major building material. Bricks should have good characteristics and good quality. One of the main characteristics of a good brick is to check the efflorescence. It is the index of its quality and should be checked by standard testing and should be classified accordingly.
Materials Required:
Bricks from different sources, water
Apparatus Required:
- Pan or tray, Scale.
THEORY:
Efflorescence: Efflorescence is the appearance of white patches on the surface of the bricks. These are due to the presence of soluble salts (such as sulfates of sodium and potassium) in the brick. It is generally common in new brickwork, but may also be formed on the face of the old external walls that are subjected to excessive dampness. For determining the presence of these salts this test is to be tested in the laboratory. From this experiment, we show that a good quality brick should not show a white salty appearance. If it shows any sign of efflorescence then it is not suitable for superior constructional work. Depending upon the percentage of exposed surface that is subjected to efflorescence in the brick.
| S.No. | Туре of Efflorescence. | Indication |
| 1 | Nil: | When there is no perceptible deposit of efflorescence. |
| 2 | Slight: | When not more than 10% of the area of brick is covered with a thin deposit of salt. |
| 3 | Moderate: | When there is a heavy deposit of salts accompanied by powdering and/or flaking of the exposed surface. |
| 4 | Heavy: | When there is a heavier deposit than mentioned under slight and covering upto 50% of the exposed area of the brick surface but unaccompanied by powdering or flaking of the surface. |
| 5 | Serious: | When there is a heavy deposit of salts covering 50% or more of the exposed area of the brick surface but unaccompanied by powdering or flaking of the surface. |
Procedure:
- Place the brick into the oven at the temperature of 105-110°C for 24 hours.
- Bring the brick back to room temperature.
- Place the brick in a 25-mm depth of water in a stainless steel dish.
- Place the brick in an inclined position.
- Do not take out the brick till the whole water evaporates from the dish or
absorbed by the brick. - Now again after the first evaporation, pour more water and let it evaporate.
- Finally, examine the brick after the 2nd evaporation.
Pre-Cautions:
Observations:
S# | DATE/DAY | WATER LEVELS (cm) | OBSERVATIONS |
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Results:
Review Questions:
- What is the Efflorescence of brick?
- State the reasons for the occurrence of Efflorescence in brick.
- Should Efflorescence, greater than “Slight” be allowed for good construction work? Justify your answer.
- Why brick is placed in an inclined position in the water tray in the Efflorescence test?
