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
- The proportion of soil and fly ash shall be as per IS-2117-1991.
- Fly ash used to manufacture of bricks shall conform to grade 1 or grade 2 as per IS-3812-1981.
- Frog size of a hand moulded brick having height of 90 mm or 70 mm shall be as per the figure shown below.
Dimensional Specification
|
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 |
Physical Requirements
| Compressive Strength | Minimum average compressive strength shall be as per various class of group (See table below)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. |
Classes of Burnt Clay Fly Ash Bricks
|
Class Designation |
Average Compressive Strength |
|
|
N/mm2 |
Kgf/cm2, (approx) |
|
|
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 |
