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

What is Brick?

  • One of the oldest building material in 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 these 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

Good bricks are used for the construction of important structures. They should possess the following qualities

    • Bricks should be table-mounted, well-burnt in kilns, copper-colored, free from cracks and with sharp and square edges.
    • Bricks should be uniform in standard size and shape.
    • Bricks should give clear sound when struck with each other.
    • Bricks, when broken, should show homogeneous and compact structure free from voids.
    • 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.
    • Bricks should be sufficiently hard. Any impression should be left on the brick surface when scratched with a fingernail.
    • Bricks should not be broken into pieces when dropped flat the hard ground height of one meter.
    • Bricks should have low thermal conductivity.
    • Bricks, when absorbed in water for 24 hours, should not show deposits of white salts when dried in the shade — dried in the shade.
    • 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 50000 bricks.
  • In case a consignment has to brick more than 50000 brick of 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

Sl. No.Range Min. Sample Collection

Table No 1.

    • The sample size for Physical Characteristics
      • Compressive Strength, Water Absorption Efflorescence. Etc.

Sl. No.Range Min. Sample Collection

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)

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

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

      • 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)

Also, read: Consistency Test of Cement

Absorption test on brick (Brick Water Absorption)

    • 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):

      • 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.

      • 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

  • Apparatus for efflorescence test on brick

          • 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

      • 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

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

1. What Is Brick Strength?

Ans: Compressive Strength of Bricks.

(i) Compressive Strength of first class brick is 105 kg/cm2.

(ii) Compressive Strength of 2nd class brick is 70 kg/cm2.

(iii) Compressive Strength of common building brick is 35 kg/cm2.

2. Which IS Code for Brick Testing

Ans: As per below IS Code used in brickwork

  1. IS: 1077 – 1992 (R2002)
  2. IS: 1200 (Part-III) – 1976
  3. IS: 2212 – 1991
  4. IS: 3495 (Part I to IV) 1992 ((R2002)
  5. IS: 6042 – 1969
  6. IS: 3590-1966
  7. IS: 3466 – 1988

3.  Different Types of  Brick Test /Is Code for Bricks/

Ans: Four Type of Brick Test as Below

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

4. Indian Standard Brick Size/ Standard Brick Size in India as Per Is Code/ Dimension of Brick.

Ans: In India, standard brick size is 190 mm x 90 mm x 90 mm as per the recommendation of BIS. With mortar thickness, the dimension of the brick becomes 200 mm x 100 mm x 100 mm which is also known as the nominal size of the modular brick.

5. Value of Water Absorption of Bricks

Ans: When tested as above, the average water absorption shall not be more than 20% by weight up to class 12.5 and 15% by weight for a higher class.

6. What is the crushing strength of a brick?


The minimum crushing / compressive strengths of burnt bricks tested flat-wise prescribed are:

(i) Common building bricks—35 kg/sq. cm,

(ii) Second class bricks—70 kg/sq. cm,

(iii) First class bricks— 105 kg/sq. cm.

(iv) Crushing strength of bricks not less than 140 kg/sq. cm are graded as AA class.

The strength of bricks decreases by about 25 percent when soaked in water.

The strength of sun-dried (unburnt) bricks is from 15 to 25 kg/sq. cm.

7. What is the importance of frog in bricks?

Ans: The depression provided in the face of brick during its manufacturing is called frog in bricks. The mortar is filled in the frog while laying the bricks in masonry work to help in bonding and acting as a shear key against horizontal loads.

  • Depth of frog in a brick 10 to 20 mm
  • The frog should be upward.

The important purpose of frog in a brick:

  • Frogs also created an extra recess for the mortar, resulting in a stronger bond between bricks ( form keyed joint between brick and mortar)
  • To reduce the weight of the bricks, so that the bricks can be laid with convenience.
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Krunal Rajput: Hey, I am Krunal Rajput. The Man Behind CivilJungle. I started this site to spread knowledge about Civil/Mechanical/Electrical Engineering. I am a Degree Holder in Civil Engineering.