Brickwork is one of the most widely used Building Materials when it comes to simple and semi-advanced construction in India. Although used for non-structural members the specifications of clay bricks play an important role in the entire construction philosophy.
The IS code which talks about the Red Clay Bricks is IS 1077 1992 (Reaffirmed 2016) "Common Burnt Clay Building Bricks- Specifications".
Classification of Bricks
Classification of Bricks is done by Designating a Class to the bricks.
Brick of Class 7.5 means that the compressive strength of the brick is 7.5 N/mm².
Characteristics of Clay Bricks
There are two categories in which clay bricks are characterized for examination:
Visual Characteristics
Physical Characteristics
1. Visual Characteristics
Dimensions of Bricks There are two sizes of bricks as per the IS code:
(a) Modular Size of Bricks
(b) Non-modular size of Bricks
Tolerance for checking Dimensions
Tolerance is checked by calculating the total dimensions of Length, Width, and Height of 20 Bricks laid in sequence along the length, width & height. Tolerance is checked as per the conditions given in the table below:
2. Physical Characteristics
(a) Compressive Strength
Compressive Strength of Clay Bricks is calculated as per the guidelines laid down in IS 3495 (Part-1): 2019
Average compressive strength of samples as per Sampling Criteria should not be less than class strength of the bricks.
Any individual brick strength comes out to be less than 15% of Class Strength.
Originally the criteria of failure was 20% as per IS 5454 Clause 5.2.1.1, however, as per the Amendment issued in 2008 for IS 1077 the criteria for failure has been made more stringent by reducing it from 20% to 15%.
(b) Water Absorption
Bricks are tested for their Water absorption criteria of Bricks characteristics
Testing is as per IS 3495 ( Part 2) : 2019
Bricks are immersed in cold water for 24 hours
(c) Efflorescence
Bricks are tested for efflorescence properties as well
