WATER ABSORPTION of aggrigate

Updated: Jul 16, 2020

2.2 WATER ABSORPTION

AIM

To determine the water absorption of coarse aggregates as per

IS: 2386 (Part III) - 1963.

APPARATUS

i) Wire basket - perforated, electroplated or plastic coated with

wire hangers for suspending it from the balance

ii) Water-tight container for suspending the basket

iii) Dry soft absorbent cloth - 75cm x 45cm (2 nos.)

iv) Shallow tray of minimum 650 sq.cm area

v) Air-tight container of a capacity similar to the basket

vi) Oven

SAMPLE

A sample not less than 2000g should be used.

PROCEDURE

i) The sample should be thoroughly washed to remove finer

particles and dust, drained and then placed in the wire

basket and immersed in distilled water at a temperature

between 22 and 32 °C.

ii) After immersion, the entrapped air should be removed by

lifting the basket and allowing it to drop 25 times in 25

seconds. The basket and sample should remain immersed

for a period of 24 + ½ hrs. afterwards.

iii) The basket and aggregates should then be removed from the

water, allowed to drain for a few minutes, after which the

aggregates should be gently emptied from the basket on to

one of the dry clothes and gently surface-dried with the

cloth, transferring it to a second dry cloth when the first

would remove no further moisture. The aggregates should be

spread on the second cloth and exposed to the atmosphere

away from direct sunlight till it appears to be completely

surface-dry. The aggregates should be weighed (Weight 'A').

iv) The aggregates should then be placed in an oven at a

temperature of 100 to 110 °C for 24hrs. It should then be

removed from the oven, cooled and weighed (Weight 'B').


REPORTING OF RESULTS

A - B

Water absorption = ———– x 100%

B

Two such tests should be done and the individual and mean

results should be reported.



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