The Compressive strength test on bricks is done in a lab and requires a specific equipment to conduct the test.
What is compressive strength of a material?
Compressive strength is the load carrying capacity of a material. For any material there is some load carrying capacity upto some extent, once this limit is reached the material starts failing.
Compressive strength of Bricks:
The ability of a material to resist failure in the form of crack or fissure is called Compressive strength. Compressive strength of bricks is the capacity of brick to withstand compression when tested in Compressive Testing Machine (CTM).
In this test the brick is placed in between the jaws of the machine, and compressive force is applied on both faces of the brick and the compressive loads on the brick is increased step by step and the maximum load at which the crack is observed on the brick is noted.
Classification of brics based on compressive strength:
According to IS: 1077-1992, based on compressive strength of brick, Bricks are classified into 11 types. They are
Bricks Class Designation | Average Compressive Strength not less than | |
| (N/mm2) | (Kgf/cm2) |
35 | 35 | 35 |
30 | 30.0 | 300 |
25 | 25.0 | 250 |
20 | 20.0 | 200 |
17.5 | 17.5 | 175 |
15 | 15.0 | 150 |
12.5 | 12.5 | 125 |
10 | 10.0 | 100 |
7.5 | 7.5 | 75 |
5 | 5.0 | 50 |
3.5 | 3.5 | 35 |
Based on compressive strength Bricks also classified as
1. First class bricks (Compressive strength = 10 N/mm2)
2. Second class bricks (Compressive strength = 7 N/mm2)
3. Building bricks (Compressive strength = 3.5 N/mm2)
4. Sundried bricks (Compressive strength = 1.5 N/mm2/ to 2.5 N/mm2 )