Test for Compressive Strength of Brick | Water Absorption | Dimensions Test

Test of Brick

What is Brick?

One of the oldest building materials in the construction line brick continues to be the most popular and leading construction material because of durable, being cheap, and easy to handle and work with.

Clay bricks are used for building up interior and exterior walls, partitions, piers, footings, and other load-bearing structures. A brick is a rectangular shape and of a size that can conveniently handle with one hand.

Brick may be made of a mixture of sand or burnt clay of sand and lime or Portland cement concrete(PPC). Clay bricks are normally used since they are economical and easily available.

The length, width, and height of brick are interrelated as below:

  • Length of brick = 2 x width of brick + thickness of mortar
  • Height of brick = width of a brick

Size of a standard brick should be 19 x 9 x 9 cm and 19 x 9 x 4 cm When placed in masonry the 19 x 9 x 9 cm brick with mortar becomes 20 x 10 x 10 cm.

However, the bricks available in most of the country still are 9″ x 4-i x 3″ and are known as field bricks.

Weight of such a brick is around 3.0 kg. (6.61 lbs) An indent called fog, 1-2 cm deep, as shown in as per below, the figure is provided for 9 cm high bricks.


Fog Detail 

The size of the fog should be 10 x 4 x 1 cm. (100 X 40 X 10 mm ) The purpose of providing frog is to generate a key for holding the mortar and so that, the bricks laid with frogs on top.

Frog is not provided in 4 cm (40mm ) high bricks and extruded bricks.

Also, read: IS Code for Civil Engineer [Q&a]

Properties of Good Bricks

  1. Good bricks are used for the construction of important structures. They should possess the following qualities
  2. Bricks should be table-mounted, well-burnt in kilns, copper-colored, free from cracks and with sharp and square edges.
  3. Bricks should be uniform in standard size and shape.
  4. Bricks should give clear sound when struck with each other.
  5. Bricks, when broken, should show a homogeneous and compact structure free from voids.
  6. Brick should not absorb water more than 15 percent of the weight for first-class bricks and 15 to 20 percent by weight for second class bricks when soaked in water for 24 hrs.
  7. Bricks should be sufficiently hard. Any impression should be left on the brick surface when scratched with a fingernail.
  8. Bricks should not be broken into pieces when dropped flat at the hard ground height of one meter.
  9. Bricks should have low thermal conductivity.
  10. Bricks, when absorbed in water for 24 hours, should not show deposits of white salts when dried in the shade — dried in the shade.
  11. The Compressive Strength of brick shall not be less than 55 kg/cm2

Also, read: Core Cutter Method

Sampling of Bricks

It is sampling a lot which shall contain a maximum of 50000 bricks. In case a consignment has to brick more than 50000 brick of the same classification, size, and manufactured under relatively similar conditions, it shall be divided into lots of 50000 bricks or part thereof.

Sampling from the stack shall be divided into a number of real or imaginary sections, and the required number of bricks shall be drawn from each section.

Bricks in the upper layers of the stack shall be removed to enable units to be sampled from places within the stack.

The sample size for Visual / Dimensional Characteristics 


Range Min. Sample Collection 
1 2001-10000 20-40
2 10001-35000 32-60
3 35001-50000 50-80

Table No 1.

The sample size for Physical Characteristics 

  • Compressive Strength, Water Absorption Efflorescence. Etc.
Sr.No. Range Min. Sample Collection 
1 2001-10000 5-10
2 10001-35000 10-20
3 35001-50000 15-30

Table No 2.

Also, read: Soundness of Cement Test

Types of Tests On Bricks

  • Compressive strength of brick
  • Water Absorption test on brick
  • Efflorescence test on bricks
  • Dimension test on bricks

Also, read: Dynamic Vs Kinematic Viscosity (Difference & Definition)

Test of brick Compressive Strength (Compressive Strength of Brick)

Relevant is Code

Is Code 3495 part 1


Compression Testing Machine(CTM)


Compression testing machine use of compress of any material as per show reding. So we know how much load in this material.


Rural scale

The scale used in this test for length, birth & depth of brick.

Wooden Plate

Wooden plate for Test

This material used for one between brick both side. Because of the edge of a brick safe in CTM (Compression testing machine)

Prework before Compressive strength of brick (brick compressive strength)

Remove observed in the bed faces to provide both smooth and parallel faces by grinding.

Immerse in the water at room temperature for 24 hours (1 Day). Remove drain and the specimen out any surplus moisture at room temperature.

Fill all voids and all fog in the bed face flush with cement mortar (clean coarse sand, the cement of grade 3 mm down ).

Store under the damp jute bag for 24 hours (1 Day), followed by immersion in freshwater for 3 days.

Wipe and Remove out any traces of moisture.

Also, read: First Angle Projection & Third Angle Projection Symbol (Orthographic Projection)

Procedure Compressive strength of brick (brick compressive strength)

Place the specimen with flat and smooth faces horizontal, and mortar filled face facing upwards between two sides 3 thick ply plywood sheets each of 3 mm thickness and carefully centered between plates of the testing machine.

Apply load uniform rate of 14 N/sq.mm. ( 140 kg f/cm2 ) per minute till failure occurs and notes the maximum load at failure.

Load at failure maximum load in brick at which to produce any further increase in the indicator read reading on the testing machine

  • Note:- Plywood sheets plaster of Paris may be used to ensure a uniform surface for the application of load.

Calculation of Compressive strength of brick (brick compressive strength)

As below calculation of test report

  • Compressive test of brick N/sq.mm. (Kgf/ sq.cm.)
    • = (Maximum load failure in Kgf (N) / Average area of the bed faced in Sq.cm ( Sq.mm)

Conclusion of  Compressive strength of brick units

Compressive strength of brick units varied from 4.3 to 6.9 MPa with an average of 5.7 MPa. Average modulus of elasticity was found to be about 3878 MPa., and bricks found to be soft and weak compared to clay bricks.

Also, read: Consistency Test of Cement 

Absorption test on brick (Brick Water Absorption)

Relevant is Code

  • Is Code 3495 part 2
  • Aim: To determine water absorption of the specimen by 24 hours immersion in cold water.
  • Scope: This procedure covers all relative activity for the project site.

Apparatus (Brick water absorption):

  • Weighing Balance

  • Weight machine for use for brick. Actual weight of the brick and after water absorption of brick weight calculation

Dry Oven


  • Dry oven use for Absorption test on brick.

Measuring scale.

Rural scale

  • The scale used in this test for length, birth & depth of brick.

Sample Preparation Absorption test on brick (Brick water absorption)

  • Dimensions shall be a measure to an accuracy of 1 mm of a test specimen
  • A dry specimen in an oven at temperature 105-1150C till it attains substantially constant mass.
  • the specimen to room cool temperature and obtain weight – M1

Procedure Absorption test on brick (Brick water absorption)

  • Immerse complete dried specimen in clean water at temperature 27+/- 20
  • Remove specimen after 24 hours and wipe out any traces of water with a damp cloth.
  • Weigh the specimen within 3 minutes after removing from water – M2

Also, read: What is Chain Surveying (Principal, Procedure, Method, Instrument)

Calculations & records Absorption test on brick (Brick water absorption)

% Water Absorption

  • = (M2-M1 /M1) x100.

Average of the results obtained shall be recorded.

All results shall be recorded in the respective Format.

Also, read: What Is Bulkage of Sand (Fine Aggregate )

Efflorescence Test On Bricks

Relevant is Code

Apparatus for efflorescence test on brick

  • Dry Oven


          • Dry oven use for Absorption test on brick.

Procedure Efflorescence Test On Bricks

Place the depth of immersion, the end of the bricks in the dish in water being 25 mm.

Place the entire arrangement in a warm (for example, 20 to 30°C) well-ventilated room so that the specimens absorbed all the water in the dish. And the surplus water evaporates.

Cover the whole dish having the brick with suitable glass cylinder so excessive hat evaporation from the whole dish may not occur.

After the water has been absorbed, and bricks appear to be dry, place the same quantity of water in the dish, and then allow it to evaporate as before.

After the second evaporation, examine the bricks for efflorescence and report the results.

Conclusion Efflorescence Test On Bricks

Nil: When the deposit of efflorescence is imperceptible.

Slight: When the deposit of efflorescence does not cover more than 10 percent of the exposed area of the brick.

Moderate: When the deposit of efflorescence is more than 10 percent but less than 50% of the exposed area of the brick.

Heavy: When the deposit of efflorescence is more than 50 percent, but the deposits do not powder or flake away from the brick surface.

Serious: When the deposits are heavy and powder or flake away from the brick surface. The specifications limit the efflorescence to be not more than moderate (10–50%) up to class 12.5 and not more than slight (< 10 percent) for higher classes

Also, read: Lab Test on Aggregates at Site 

Dimension Test On Bricks

Relevant is Code


  • Measuring scale.

Rural scale

  • The scale used in this test for length, birth & depth of brick.

Procedure Dimension Test On Bricks

20 pieces out of selected pieces (Table No 1.) are taken and are laid flat as shown in Figure No.1

Dimension Test On Bricks

2 c Measurement of Hight 

Dimension Test On Bricks Figure No.1

 The tolerances (as per below) on the sizes of bricks are fixed by giving minimum and maximum dimensions, not on individual bricks but on batches of 20 bricks chosen at random.

  • For modular size
    • length 3720 to 3880 mm (3800 ± 80 mm)
    • Width 1760 to 1840 mm (1840 ± 40 mm)
    • Height 1760 to I 840 mm (1840 ± 40 mm) ( For 90 mm high bricks)
      • 760 to 840 mm ( 800 ± 40mm) ( For 40 mm high bricks)
  • For non-modular size
    • Length 4520 to 4680 mm ( 4600 ± 80 mm )
    • Width 2240 to 2160 tum (2200 ± 40 mm)
    • Height 1440 to 1360 mm ( 1400 ± 40 mm )
        • ( For 70 mm high bricks )
      • 640 to 560 mm ( 600 ± 40 mm)
        • ( For 30 mm high bricks)

Twenty entire bricks shall be selected at random from the sample selected under 8. Loose particles, all blisters of clay and small projections shall be removed.

They shall be arranged upon a level surface successively as indicated in please above figure. 2C, 2B, and 2A in contact with each other and in a straight line. (As per Figure)

The overall (Stright Brick) length of the assembled bricks shall be measured with a tape, other suitable inextensible measure sufficiently (Electronic measurement tape) long to measure the entire row at one stretch.

Measurement by repeated application of short rule or measure shan’t be permitted.

If, it is found impracticable to measure bricks in one row, the sample may be divided into rows of ten (10) bricks each which shall be measured separately to the nearest mm(millimeter).

All these dimensions shall be added together.

Also, read: Procedure for Rcc Concrete

Test on Bricks PPT

Common Burnt Clay Bricks Detail / Strength

Average Compressive Strength
not Less Than
N/ Sq.mm. Kgf / Sq.cm.
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
The common burnt clay bricks shall be classified on the basis of average compressive strength as given in the above table

Also, read: What Is Traversing in Surveying | Types | Method | Definition


What Is Brick Strength?

The compressive strength of brick or structural clay tile is an important material property for structural applications. In general, increasing the compressive strength of the unit will increase the masonry assemblage compressive strength and elastic modulus.

Which IS Code for Brick Testing?

As per below IS Code used in brickwork

  • IS: 1077 – 1992 (R2002)
  • IS: 1200 (Part-III) – 1976
  • IS: 2212 – 1991
  • IS: 3495 (Part I to IV) 1992 ((R2002)
  • IS: 6042 – 1969
  • IS: 3590-1966
  • IS: 3466 – 1988

Different Types of  Brick Test

Types of Tests On Bricks for Construction Purpose

  • Absorption test.
  • Crushing strength test.
  • Hardness test.
  • Shape and size.
  • Color test.
  • Soundness test.
  • Structure of brick.
  • Presence of soluble salts (Efflorescence Test)

Indian Standard Brick Size

Bricks Sizes as per Indian Standard (IS 1077) Brick sizes based on IS 1077 specification (Common burnt clay building bricks), the standard modular size of common building brick is 190 x 90 x 90 mm or 190 x 90 x 40 mm (length x depth x height).

Value of Water Absorption of Bricks

The acceptable water absorption for clay bricks are between 12% and 20%. If you are using engineering bricks the closer you are to the 12% the better the result will be. When the water absorption is too low, i.e. below 12%, it may be difficult to obtain a proper bond between the mortar and the bricks.

What is the Crushing Strength of a Brick?

Typically, compressive strength or crushing strength of brick is ranging between 1000 psi to 1500 psi, in general, compressive strength of 1st class brick is around 1493 psi, for common building bricks, their compressive strength is around 498 psi, for second class brick, their compressive strength is around 996 psi, for sun dried brick, their compressive strength is around 356 psi, for fly ash brick, their compressive strength is around 1422 psi and for AAC block, their compressive strength is around 570 psi.

What is the Importance of Frog in Bricks?

frog is a depression in one bearing face of a molded or pressed brick. The frog reduces the weight of the brick and makes it easier to remove from the forms. ASTM specifications C 62 (building brick), C 216 (facing brick), and C 652 (hollow brick) all set limits on the size of frogs

Water Absorption Test on Bricks

Water absorption test on bricks are conducted to determine durability property of bricks such as degree of burning, quality and behavior of bricks in weathering. A brick with water absorption of less than 7% provides better resistance to damage by freezing.

 Standard Brick Size in India as Per Is Code

The Bureau of Indian Standards has brought out a number of standards on dimensions, quality, strength, classifications, grading and methods of test for metric bricks. ZS 1077 : 1986 and IS 2180 : 1985 suggest two sizes of common building burnt clay bricks, namely 200 mm x 100 mm x 100 mm and 200 mm x 100 mm x 50 mm.

 Dimension of Brick

Bricks Compressive Strength

Compressive Strength/ crushing strength of first class brick is 105 kg/cm2. (ii) Compressive Strength/crushing strength of 2nd class brick is 70 kg/cm2. (iii) Compressive Strength/crushing strength of common building brick is 35 kg/cm2

Compressive Strength of Brick

  1. Compressive Strength/ crushing strength of first class brick is 105 kg/cm2.
  2. Compressive Strength/crushing strength of 2nd class brick is 70 kg/cm2.
  3. Compressive Strength/crushing strength of common building brick is 35 kg/cm2.
  4. Compressive Strength/crushing strength of sun dried brick is 15 to 25 kg/cm2.

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