EFFLORESCENCE

V. EFFLORESCENCE

1. Efflorescence Test of Brick as per ASTM C 67:

1.1 Test Specimens: The sample shall consist of ten full-size bricks. The ten specimens shall be sorted into five pairs so that both specimens of each pair will have the same appearance as nearly as

possible.

1.2 Preparation of Specimens: Remove any adhering dirt that might be mistaken for efflorescence by brushing. Dry the specimens and cool them as prescribed earlier.

1.3 Procedure:

1.3. 1 Set one specimen, each of the five pairs, on end, partially immersed in distilled water to a depth of approximately 25.4 mm (1 in.) for 7 days. When several specimens are tested in the same

container, separate the individual specimens by a space of at least 50.8 mm (2 in.). Store the second specimen from each of the five pairs in the drying room without contact with water. At the end of 7 days, inspect the first set of specimens and then dry both. sets in the drying oven for 24 hours.

NOTE: Do not test specimens from different sources simultaneously in the same container, because specimens with a considerable content of soluble salts may contaminate salt-free specimens.

1. 3. 2 Examination and Rating: After drying, examine closely and compare each pair of specimens, observing the top and all four faces of each specimen. If there is no observable difference due to efflorescence, report the rating as "no efflorescence. "If any difference due to efflorescence is noted, view the specimens from a distance of 3 m under the illumination of not less than 538.21 m/m^2 (50foot-candles) by an observer with normal vision. If under these conditions no difference is noted, report the rating as "slightly effloresced". If' a perceptible difference due to efflorescence is noted under these conditions, report the rating as effloresced". Record the appearance and distribution of the efflorescence.

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2. Efflorescence Test of Brick as per Bangladesh Standard (BDS 208, 1980):

2. 1 Test Specimen: Test specimens shall consist of 5 whole dry bricks which shall be tested for efflorescence as described below.

2 2 Procedure: Each brick shall be placed on end in a shallow lat bottom non-absorbent dish keeping a minimum clearance of 5 cm (2 inches) between two consecutive bricks. Distilled water shall then be poured to depth of 2.54 cm(1 inch) so that 1t surrounds each brick by one inch. only. The whole arrangement shall be allowed to stand in a well-ventilated room at about 15°C-20°C. After a few days when the water has been absorbed and the bricks appear to be dry, a similar quantity of water shall again be poured into the dish and further drying period allowed. The bricks shall then be examined for efflorescence.

2.3 Observation and Results: The tendency to efflorescence shall be reported as "Nil", "Slight"

"Moderate", "Heavy" or "Serious" in accordance with the following definitions:

Nil: No perceptible deposit of efflorescence.

Slight: Not more than 10 percent of the area of the bricks covered with a thin deposit of salts.

Moderate: A heavier deposit than under "Slight" and covering up to 50 percent of the brick surface

but unaccompanied by powdering of flaking of the surface.

Heavy: A heavy deposit of salts covering 50 percent or more of the brick surface but unaccompanied by powdering or flaking of the surface.

Serious: A heavy deposit of salts accompanied by powdering and/or flaking of the surfaces.

NOTE: If the observed efflorescence varies in each specimen, the worst affected specimen shall form the basis of this report.