5-Hour Boiling Water Test
The specimen is dried within an oven at 105 to 115oC till it attains constant mass. At room temperature cool the specimen and record its weight (W1). The brick is immersed in boiling water for 5 hours. The water is permitted to cool at 27 ± 2oC with brick immersed. The brick is taken out and wiped along with damp cloth. Full the weighing of the specimen in three minutes. Now let it be W3.
Water absorption, percent by mass, is given through
W3 - W1/ W1 × 100