Efflorescence Test of Fly Ash Brick As Per IS Code 3495 Part-3

Civil Engicon Team
By -
Update: May 13, 2023
In this post we will read about the fly ash brick test as per IS Code 3495 Part-3 (Efflorescence Test of Fly Ash Brick). Also, we will know how to examine the efflorescence of fly ash bricks and some relevant topics like causes and treatment of efflorescence.

Fly Ash Brick Test As Per IS Code 3495 Part 3 (Efflorescence Test of Fly Ash Brick)

Efflorescence test of fly ash brick is the examination of salt deposition at the surfaces of brick under a specific condition in laboratory. This is not a quick test because it takes at least one week to evaporate the water from the dishes. Read complete post to know more about efflorescence of brick.

Efflorescence Test of Fly Ash Brick As Per IS Code 3495 Part-3
Fly Ash Brick Test

Meaning of Efflorescence in Brick

Efflorescence is the deposition of salt at the surface of bricks. It may occur due to the contact of brick with moisture from any source like atmospheric air, surface water, sewage water or ground water.  The moisture comes from ground to upside through the brick work by capillary action of water. The efflorescence in brick can be seen easily as white salt deposition at the surface of brick . Due to salt deposition at the brick surfaces, the bricks become weak and the brick structure also started to become weak over the time.

Standard Procedure For Efflorescence Test of Fly Ash Brick

Aim of the Test:

To Determine the Efflorescence of fly ash bricks as per IS Code 3495 Part-III.

Indian Standard Used in Efflorescence Test

  • IS: 5454 - 1978 [Method for Sampling of Clay Bricks]
  • IS: 3495 (Part 3) - 1992 [Method of Test of Burnt Clay Building Bricks]
  • IS: 13757 - 1993 [Burnt Clay Fly Ash Building Bricks- Specifications]

General Requirements for Efflorescence Test of Fly Ash Brick

  • The dimensions of the bricks shall be measured to the nearest 1 mm.
  • All apparatus and testing equipment shall be calibrated at frequent intervals.
  • The number of specimens for the test shall be selected as per IS: 5454 - 1978.
Sampling Table For Efflorescence Test of Fly Ash Brick

Apparatus Required For Efflorescence Test of Fly Ash Brick

  1. Dishes (Shallow flat bottom dishes which contain sufficient distilled water to completely saturate each specimen of the sample.The dishes should be made up of glass, porcelain or glazed stoneware and its size should be 180 mm x 180 mm x 40 mm depth for square shaped and 200 mm diameter x 40 mm depth for cylindrical shaped.)
  2. Glass Cylinders (To Cover the Vertical Part of Bricks from Top)

Formula For Efflorescence Test

No formula is there to calculate efflorescence. Visual inspection is used to examine the efflorescence test of brick. 

Efflorescence Test of Brick Procedure

Step 1: Each bricks should be kept vertically in the dishes. The depth of immersion of brick in water should be 25 mm.

Step 2: After that place the whole arrangement of the test in a warm (Approx 20°C to 30°C) and well ventilated room until the water in dish is absorbed by each specimen and the surplus water evaporates. 

Step 3: Cover each brick in the dish with a suitable glass cylinder so that evaporation from the dish may not occur.

Step 4: When the water has been absorbed and bricks appear as dry, place a similar quantity of water in the dish and allow it to evaporate again as before.

Step 5: After the second time evaporation, examine the bricks for efflorescence and report the results of each.

Fly Ash Brick Test Result

The efflorescence test result of brick is either Nil, Slight, Moderate, Heavy or Serious.

Examine the Efflorescence of Bricks

Efflorescence is examined by the help of deposited salt in different percentage of exposed area of brick.

Nil: The Result is "Nil" When there is no perceptible deposit of efflorescence is found on the brick.

Slight: The Result is "Slight" When maximum 10% exposed area of the brick is covered with a thin salt layer.

Moderate: The Result is "Moderate" When there is a heavier deposit compare to "Slight" and it is covering up to 50% of the exposed area of brick but unaccompanied by powdering or flaking of the brick surface.

Heavy: The Result is "Heavy" When there is a heavy deposit of salt which covers 50% or more than 50% of the exposed area of the brick surface but unaccompanied by powdering or flaking of the brick surface.

Serious: The Result is "Serious" When there is a heavy deposit of salt accompanied by powdering and or flaking of the exposed surfaces of the brick.

Efflorescence Test Report

The test results obtained from each specimen shall be reported accordingly nil, slight moderate heavy or serious.

Test Requirements of Fly Ash Brick

As per IS: 13757 - 1993 [Burnt Clay Fly Ash Building Bricks- Specifications], The brick test accordance with the procedure as per IS: 3495 (Part 3)- 1992, After second time evaporation of water from the dish the rating of efflorescence shall not be more than "moderate'' up to class 12.5 and "slight'' for higher classes.

Causes of Efflorescence in Bricks

Efflorescence in bricks is caused by the migration of soluble salts present in the building materials or soil to the surface of the bricks through capillary action.
When water infiltrates the bricks or mortar, it dissolves the salts and carries them to the surface where the water evaporates leaving behind the salt deposits and this results as a white or grayish powdery deposit on the surface of the bricks. Factors such as high humidity, rain, snowfall, insufficient ventilation or drainage can contribute to the formation of efflorescence at the brick surfaces.

Treatment Efflorescence in Bricks

The treatment of efflorescence in bricks depends on the severity of the problem. Here we are providing some common methods to treat efflorescence of bricks.

Brushing and Watering Treatment: Light efflorescence can be treated by brushing the bricks with a stiff-bristled brush and water. This can remove the salt deposits from the surface.

Acid Wash Treatment: An acid wash can be used to remove more severe efflorescence. A dilute solution of hydrochloric acid can be applied to the affected area and left for a short time before being washed off with water.

Sealing Method: Sealing the bricks can prevent water from infiltrating and dissolving the salts. There are many types of sealers available such as silanes, siloxanes and acrylics which can penetrate the surface of the bricks and create a barrier against moisture.

Professional Cleaning: If the efflorescence is severe and cannot be removed by the above methods, it may be necessary to call a professional cleaner who can use specialized equipment to remove the deposits.

It is important to note that efflorescence is a symptom of a deeper moisture problem. Therefore, it is important to identify and address the source of the moisture to prevent future efflorescence. This can be by improving drainage around the building or repairing leaky pipes.


How to Prevent Efflorescence in Construction?

Efflorescence in bricks can be prevented by using high-quality building materials that having low salt content and are well-dried before installation. Proper ventilation and drainage systems must be installed to prevent moisture buildup in the building structure. The building's exterior should also be cleaned and maintained regularly to prevent efflorescence. Also, it is important to ensure that the brickwork is protected from water during and after construction to prevent water infiltration.


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