Salahaddin University-Erbil
College of Engineering
Department of Civil Engineering
Construction
Materials
Properties and Testing
Test No.:3
Efflorescence of Clay brick
Prepared by :Salwa Mzafar
Group No,:B2
Name of the students:
1. Salwa Mzafar
2. Soma Muhammad
3. Sardar Mahir
4.
Introduction:
1. Efflorescence is a whitish crystalline deposit on surface of the bricks ,usually magnesium
sulphate.
2. Efflorescence caused by water soluble salts and other water dispersible that come to
the surface of bricks .
3. It is generally a white or off-white colour with powdery appearance .
4. Water moves and migrates through channels in brick carrying the salt to the surface .
5. Efflorescence , once it becomes insoluble ,is more difficult to remove but evaporation is
the solution to move the efflorescence.
Test objective:
The objective of this test is to see and observe the the deposit of the salt that lying on surface
of the brick.
Requirements:
1. This test is done according to the ASTM C 97-09 and Iraqi standard specification
24/1988, standard test methods for testing bricks and sampling structural clay tile.
2. The selected specimens should be representative of a lot of units and brushed to
remove dirt ,mud ,mortar and any foreign materials.
3. According to the ASTM the number of selected specimen at least 10 individual bricks for
lots of 1000 000 bricks or fruction.
4. The test specimen shall consist of ten full size bricks that shall be stored in to five pairs
so the both specimens of each pair will have the same appearance as nearly as possible
and brush any adhering dirt.
Apparatus:
1. Tray and containers :the properties of the of the trays or pans as follow:
2. The material of water tight shallow pans or trays must be corrosion –resistant metal
that will not provide soluble salts when when in contact with distilled water containing
leaching with brick .
3. The pan shall provide an area such that the total volume of water is large in
compression with the mount evaporated each day so it will provide not less than 25.4
mm depth of water .Suitable apparatus shall be provides for a constant level of water in
the pan .
4. Drying room ,maintained at a temperature of 24-+8 with a relative humidity between
30 to 70%.
5. Drying oven ,that provides a free circulation of air through the oven and is capable of
maintaining a temperature between 110 to 115.
Procedure:
1.Select 10 bricks randomly.
2. Set
each specimen from each of the five pairs on end and partially immersed in distilled water to a
depth approximately 25mm for a week in a drying room separated the individually by a spacing
of at least 50.8mm.
3. Set other specimen from each of the five pairs in the drying room with out contact with
water .
4. At the end of the 7 days inspect the first set of the specimen and then dry both sets in drying
oven for 24 hours.
5. After drying examine and compare each pair of specimen from a distance of 3munder good
illumination by an observer with normal vision.
Result:
1. If there is not noticeable deposit of efflorescence .
2. Slight-when less than %10of exposed area of brick is covered by a thin layer of salt.
3. Moderate –when there is a heavier deposit than under slight and covering up to 50
percent of the exposed area of the brick surface but unaccompanied by powdering or
flaking of the surface .
4. Heavy-when there is a heavy deposit of salts covering %50percent or more of the
exposed area of the brick but unaccompanied by powdering or flaking of the surface.
5. Serious-when there is a heavy deposit of salt acquired by powdering and flaking of
exposed surface.
Specification:
According to Iraqi standard specification 25/1988 the maximum efflorescence of the clay brick
illustrated as follow:
Iraqi standard specification Efflorescence
(Maximum)
Class A Used to structure parts and foundation loaded and exposed to slight
erosion because of climatic effects and for external walls exposed
to erosion
Class B Used for bearing structure parts unexposed for erosion or for Medium
internal wall protected from moisture.
Class C Used for structure parts unexposed to climatic effects and ------
unloaded as a partition.
