Compressive Strength test on brick

Compressive strength test on bricks is performed to know the crushing strength of bricks which should not be less than the specified limit. This test is performed as per IS 3495 part 1.

Procedure:

1. Take 5 bricks from the samples already taken at random.
2. Immersed them in water at room temperature for 24 hours
3. After 24 hours, take them out of the water and wipe off the surplus moisture.
4. Fill the frog and all the voids in the brick with cement mortar 1:1 (1 cement, 1 clean coarse sand of grain in size 3 mm or small)
5. Store the bricks under sacks for 24 hours
6. After the expiry of 24 hours, immerse them in water for 3 days.
7. At the end of 3 days, bricks are taken out and wiped dry and place with flat surface horizontal and the mortar filled face upward between 2 or 3 plywoods sheets, each approximately 3 mm thick and carefully centred between the plates of compression testing machine.
8. The load is applied at a uniform rate of $\text{14 }N/m{{m}^{2}}$ per minute until failure occurs.

                      $\text{Compressive Strength =}\frac{\text{Maximum load at failure}}{\text{average area of the bed face}}$

The compressive strength of any individual brick shall not fall below average compressive strength specified for the corresponding class of bricks by more than 20%. 

Compressive strength of first-class brick and second class brick shall not be less than $10.5 N/{{mm}^{2}}$ and $7.5 N/{{mm}^{2}}$ respectively.

Classification of common burnt bricks on the bases of compressive strength as per IS 1077 

 

Class Designation	Average Compressive Strength, $N/{{mm}^{2}}$
35	35
30	30
25	25
20	20
17.5	17.5
15	15
12.5	12.5
10	10
7.5	7.5
5	5
3.5	3.5

prev 1 2 3 4 next