Classification and Characteristics of Bricks as per IS1077-1973

🕑 Reading time: 1 minute

Classification and Characteristics of Bricks as per IS 1077-1973

Tests for the acceptance of bricks for building construction are:

1. Dimension and tolerance test
2. Compressive strength test
3. Water absorption test
4. Efflorescence test

1. Dimension and Tolerance Test on Bricks

Take 20 bricks out of given sample. The dimensions of 20 bricks should be within the following limits.

Class	Length	Width	Height
Class A	380 +/- 12mm i.e. 368 to 392 mm	180 +/- 6mm, i.e. 174 to 186 mm	174 to 186 mm
Class B	380 +/- 30mm, i.e. 350 t0 410 mm	80 +/- 15mm, i.e. 165 to 195 mm	165 to 95 mm

2. Compressive Strength Test on Bricks

The compressive strength of a common brick should be 50 kg/sq.cm

3. Water Absorption Test on Bricks

If the water absorption capacity of a brick is more, its strength will be comparatively low. For first class bricks, the water absorption capacity should not be more than 20% by weight.

4. Efflorescence Test on Bricks

This test is performed to know the presence of of any alkaline matter in the bricks. Procedure:

1. Take five bricks at random from the given sample.
2. Place each brick on end in a dish containing distilled water ensuring depth immersion at least 2.5cm.
3. Keep the dish in a ventilated room (temperature 20 deg to 30 deg C) till the whole of distilled water in the dish evaporates.
4. Again pore 2.5 cm depth of distilled water in the dish and keep it till whole of water gets evaporated.
5. Now examine the bricks for efflorescence as detailed below:

OBSERVATION	RESULT
No perceptible deposit	Nil – efflorescence
10% are covered with deposit of salts	Slight – efflorescence
50% area covered with deposits of salts without any powdering or flaking surface	Moderate – efflorescence
50 % area covered with deposit of salts accompanied by flaking of surface	Heavy – efflorescence
Heavy deposits of salts accompanied by flaking of the surface	Serious – efflorescence

Terra Cotta made from a mixture of fine clay 60%, crushed pottery 20%, while sand 14% and powdered glass 6% with a quantity of desired colouring substance. It is baked earth of superior variety of clay. Terra-cotta is used for architectural and ornamental parts of superior building as a substitute for stones. It is used as sound proof material and its hollow blocks prevent dampness in the structure.