Water absorption test

IS code of Water absorption test is 1077-1992.

Water absorption test is done on bricks to find out the amount of water that will be absorbed by them under extreme conditions. In this, dry bricks are taken and weighed, and then placed in water and then weighed. The difference between the wet and dry brick's weight will give the compressive strength of the brick. The ideal water absorption rate for a brick is 20% the weight of the dry brick. It can be performed using 2 methods

Crushing strength test

IS code of crushing strength test is 1077-1992.

The crushing strength of a brick is determined by placing it in a compression testing machine. The top and bottom of the brick are ground to give the brick a proper shape and then kept in water at room temperature for 24 hours. These are taken out and the water is drained. Then the voids are filled with a layer of 1:1 mortar. These are allowed to be hardened and then placed in water for 7 days. After 7 days, these are taken out and placed in the compressive testing machine to measure the compressive strength. The minimum crushing strength of brick is 3.50 N/mm². If it is less than that, it isn’t useful.

Compressive strength= maximum load at failure/ base of the brick 

Hardness test

IS code of Hardness test is 1077-1992.

A good quality brick resists scratches against sharp objects. Any sharp object like an iron nail, broken glass or steel is used for this. If there is no scratch, then the brick is considered to be of good quality. 

Colour test

IS code of Colour test is 1077-1992

Colours are good indicators of the quality of brick. Bricks that are strong and burnt properly have uniform colours throughout their body, and these colours vary from dark red to light brown.

Soundness test

IS code of Soundness test is 1077-1992.

A soundness test is conducted to check the nature of the brick against sudden impact. It is done by striking two bricks together. They should produce a ringing sound upon striking each other. Also, if a brick falls onto the ground from a height of 1 metre, then it shouldn’t break or have an impact on the brick.

Shape and size test

IS code of Shape and size test is 1077-1992.

The faces of the brick should be a rectangle along with sharp edges. And the dimensions should be of Indian standard, which is 190mm x 90mm x90mm. For this test, 20 bricks are stacked together along their length, breadth and height, and are then compared.

Structure test

IS code of Structure test is 1077-1970.

To check the structure of a brick, a brick is thrown on the ground and broken from the middle. If the brick is homogeneous and free from any lump, then it is considered to have a good structure.

Test for the presence of soluble salts

IS code of Soluble salt test is 1077-1970.

It is also called the efflorescence test. It is done to check the presence of soluble salts. If there is the presence of soluble salts, then there will be an efflorescence of the bricks. To check the presence of soluble salts, the bricks are kept in a water bath with a regulated temperature between 20 to 30 degrees celsius till the water is absorbed or evaporated. After drying up, a similar amount of water is once again added to the specimen. The efflorescence is denoted as nil, slight, moderate, heavy or serious. The given magnitudes are placed in increasing levels of efflorescence.