Water Absorption Test on Bricks

Water Absorption Test on Bricks

Water absorption test on bricks is conducted to determine the durability property of bricks such as degree of burning, quality and behaviour of bricks in weathering. A brick with water absorption of less than 7% provides better resistance to damage by freezing. The degree of compactness of bricks can be obtained by water absorption test, as water is absorbed by pores in bricks. The water absorption by bricks increases with the increase in pores. So, the bricks, which have water absorption less than 3 per cent can be called as vitrified. This test provides the percentage of water absorption of bricks and the procedure of the same is discussed below.

Apparatus

A sensitive balance capable of weighing within 0.1% of the mass of the specimen and ventilated oven

Specimen

Three numbers of whole bricks from samples collected for testing should be taken.

Procedure of Water Absorption Test

1. Dry the specimen in a ventilated oven at a temperature of 105 °C to 115°C till it attains substantially constant mass.
2. Cool the specimen to room temperature and obtain its weight (M1) specimen too warm to touch shall not be used for this purpose.
3. Immerse completely dried specimen in clean water at a temperature of 27+2°C for 24 hours.
4. Remove the specimen and wipe out any traces of water with a damp cloth and weigh the specimen after it has been removed from water (M2).

Calculation of Water Absorption of Bricks

Water absorption, % by mass, after 24 hours immersion in cold water is given by the formula,

                                                                    

The average result shall be reported.

Result

Water absorption of the given bricks = ………….%

Water Absorption Values for Bricks

When tested as above, the average water absorption shall not be more than 20% by weight up to class 12.5 and 15% by weight for the higher class.