How to Determine the Water absorption of the Brick (ASTM C-67-80)

Objective: 

 There are following objects for determining the water absorption of the brick.
(1) To finding the capacity of water moisture that a brick can store.
(2) Finding the standard water moisture of the brick. Good brick store water moisture not more than 15% of their weight.

Apparatus:

 Following apparatus are used to determination of water absorption of brick.

(1) One weighing machine.
(2) Small towel.
(3) Water bowl.

Signifience:

Water absorption of bricks depends of brick following factors.

(1) Chemical composition of brick clay.

(2) Porosity which is due to voids in the brick which are result of impurities. More or large voids cause more water absorption. The number and size of these voids greatly affect strength of brick. Generally water absorption may vary from 10-15% according to voids.

Test Specimen:-

The test specimen shall consist of a brick.

Procedure:-

Dry the test specimen to a constant weight in the ventilated oven at 110-115 degree centigrade.when cooled weighs each specimen. This weight is known as dry weight (W1).

It can be assumed that heating for 72 hours at these temperatures will assure constant weight. Store the bricks unstacked with separate placement in a ventilated room for a period of 4 hours with a current of air from an electric fan passing over them for a period of at least 2 hours. Cool the specimen at room temperature. Submerge the dry specimen in clean water at 15.5-30 degree centigrade for 24 hours. Remove the specimen, wipe off the surface water with a damp cloth and weigh specimen. Weighing of any one specimen shall be completed within five minutes after removing the specimen from water bath. This will be known as wet weight (W2).

The percentage of water absorption can be calculating using the following relation.

Water absorption percentage= (W2-W1/W1)100

   Where,

                                           Dry weight = W1

                                           Dry weight = W2  

Sr. No.	Sample name	W1(g)	W2(g)	W2-W1/W1	(W2-W1/W1)×100
1	S	3257	3539	0.086	8.6
2	P	3117	3548	0.138	13.8
3	RK	3180	3530	0.11	11

Precautions:-

1- First of all remove the dust on the brick surface carefully.

2- Wife off the surface of wet specimen with a damp cloth carefully.

3- Temperature and time duration should be accurate in the experiment, decide by the ASTM.

4- Water should be neat and clean and free from different impurities.

Note: Readings of the above table is obtained in laboratory after performing this job.