Water Absorption of Bricks

Dried bricks are weighed, immersed in water for 24 hours, then removed, wiped and weighed again. The increase in weight, expressed as a percentage of the dry weight, is the water absorption.

IS 3495 sets a maximum absorption limit for each brick class, since highly absorptive bricks are more prone to efflorescence, frost damage and general deterioration over the life of the structure. This test is normally run alongside the compressive strength test on the same sample batch.