WHAT ARE THE QUALITY REQUIREMENTS OF COMMON CLAY BUILDING BRICKS?

QUALITY REQUIREMENTS OF COMMON BURNT CLAY BUILDING BRICKS

1. General Quality

  • Bricks shall be free from cracks and flaws and nodules of free lime.
  • Bricks shall have smooth rectangular faces with sharp corners
  • Bricks shall be uniform in colour
  • Frog size of a hand moulded brick having height of 90 mm or 70 mm shall be as per the figure shown below.
Frog Size for Common Burnt Clay Building Bricks
Frog Size for Common Burnt Clay Building Bricks

 

 2. Dimensional Specification

Bricks can be of modular size or non-modular size. The size of individual brick must conform to the dimensions as given in the following table.

Dimension for Modular Bricks
Length (L), mm Width (W), mm Height (H), mm
190 90 90
190 90 40
Dimension for Non-Modular Bricks
Length (L), mm Width (W), mm Height (H), mm
230 110 70
230 110 30

3. Physical Requirements

When common clay building bricks are tested for its physical characteristics, they should satisfy the following quality requirements, as given in the table below.

Compressive Strength Compressive strength of any individual brick shall not be less than the minimum compressive strength for the corresponding class of brick. (See table below)
Water Absorption Shall not be more than 20% by weight up to class 12.5 and 15% by weight for higher classes.
Efflorescence Shall not be more than ‘moderate’ up to class 12.5 and ‘slight’ for higher class.

4. Classes of Common Burnt Clay Bricks

On the basis of its average compressive strength, bricks are classified into following classes as shown in the table below. When tested for compressive strength test, brick should fall into any of the following classes.

Class Designation Average Compressive Strength
N/mm2 Kgf/cm2, (approx)
35 35 350
30 30 300
25 25 250
20 20 200
17.5 17.5 175
15 15 150
12.5 12.5 125
10 10 100
7.5 7.5 75
5 5 50
3.5 3.5 35

Reference

IS: 1077-1992

 

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