Specification For Burnt Clay Fly Ash Building Bricks (IS-13757-1993)

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.
Frog Size for Burnt Clay Fly Ash Building Bricks
Frog Size for Burnt Clay Fly Ash Building Bricks

 

 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

 

Fly Ash Bricks
Fly Ash Bricks

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