Test of Bricks: Field Test and Laboratory Test

As we all know, Brick is used to construct the wall, foundation, etc. In RC frame Building Brick wall is used as infill material. It resists the Tension and Compression forces. Test of Bricks

Field Test of Bricks

Shape and Size Test

  • Good quality of bricks should have a uniform in size and have rectangular faces. It shall be checked by doing observation.

Color Test

  • Good quality of Bricks should have a uniform in color throughout. A check shall be made before purchasing the bricks.

Sound Test

  • Bricks should have a metallic ring when one brick stuck against another brick. The dull sound shows a bad quality.

Structure

  • Bricks should be free from holes, lumps, or grit.
  • Broken bricks if observed shall be removed and not be used for masonry work.

Hardness Test

  • In this test, scratch shall be done on bricks with a nail. If no impression is marked on the surface that shows good quality and adequate hard surfaces.

Efflorescence Test

Bricks shall be placed in a glass dish having water to a height of 25 mm in a well-ventilated room. After some hours, water is absorbed or gets evaporated; again water is added for a depth of 1 inch. After the second evaporation, a white/grey patch is observed in bricks. Efflorescence shall be reported as ‘

Nil: No patches.

Slight: Not more than 10% of the area covered with deposit slats.

Moderate: 10 to 50% of area bricks but unaccompanied by powdering or flaking of the surface.

Heavy: more than equal to 50% of the area of bricks but unaccompanied by flaking of the surface

Serious: Heavy deposit of salt accompanied by powdering the exposed surfaces.

Laboratory Test of Bricks

Dimension Test of Bricks

Following are the procedure of Dimension test of bricks

  • In this test, twenty numbers of bricks shall be randomly selected from the stack sample.
  • Loose particles of clay, sand, and blisters shall be removed from the surface of bricks.
  • All the bricks shall be arranged on the leveled surface. All bricks shall be close with each other and should be in a straight line.
  •  The length of the laid 20 bricks shall be measured with Measurement Tape. If found any kind of technical problem to measure the bricks in one row, then a sample of 20 bricks shall be divided in two-row of 10 bricks each which shall be measured separately.
  • Measurement shall be done in lengthwise, widthwise, and height wise separately.

 The tolerance in the dimension of the 20 bricks shall be within the following limits.

For Modular Size of Bricks
 (190 mm x 90 mm x 90 mm and 190 mm x 90 mm x 40 mm)
Measurements of 20 bricksTolerance Value
Along Length190 x 20 = 3800 mm3800 mm + 80 mm
Along width90 x 20 = 1800 mm1800 mm + 40 mm
For 90 mm height bricks90 x 20 = 1800 mm1800 mm + 40 mm
For 40 mm height bricks40 x 20 = 800 mm1800 mm + 40 mm
For Modular Size of Bricks  
(230 mm x 110 mm x 70 mm and 230 mm x 110 mm x 30 mm)
Measurements of 20 bricksTolerance Value
Along Length230 x 20 = 4600 mm4600 mm + 80 mm
Along width110 x 20 = 2200 mm2200 mm + 40 mm
For 70 mm height bricks70 x 20 = 1400 mm1400 mm + 40 mm
For 30 mm height bricks30 x 20 = 800 mmmm + 40 mm

Water absorption Test

Following are the procedure of water absorption test of bricks:

  • Code of Reference: IS 3495 (Part 2): 1992.
  • Apparatus required: Weighing Balance, Specimen, and oven dry.
  • The specimen shall be dried in an oven-dry at a temperature of 105 to 1150 C till it achieves substantially constant mass.
  • The specimen shall be cooled to room temperature of 27+20 C.
  • After cooling the specimen in Room temperature and measure the weight of the specimen say (W1).
  • Now the dried specimen shall be immersed in a clean temperature of 27+20 C for up to 24 hours.
  • The specimen shall be removed after 24 hours and wipe out with dry clothes and measure the weight say W2. The weighing of the specimen shall be completed within 3 minutes after removal from water.
  •  Water absorption in percentage after 24-hour immersion in cold water is calculated by the following formula
  •                 Water absorption(%)= (W2-W1/W1)  x 100
  • It shall not be more than 20% by weight up to class 12.5 and 15 percent by weight of higher classes.

Compressive Strength of Bricks

The procedure of compressive strength test of bricks are as follows;

  • Code of Reference: IS 3495 (Part 2): 1992.
  • Apparatus required: Compression Testing Machine (CTM), Specimen.
  • Brick is immersed in water at room temperature for 24 hours. It shall be removed and drain out any surplus moisture at room temperature.
  • The frog of bricks is filled flush with 1 part of cement and 3 part of sand.
  • The specimen shall be stored under the damp jute bags for 24 hours and immersed in clean water for 24 hours and then wipe out the moisture with dry clothes.
  • Brick is then placed on a compressive testing machine with 6 mm plywood on top and bottom of it in order to get a uniform load on the specimen.
  • The Axial load then be applied at a uniform rate of 14 N/mm2 per minute till the failure occurs. The maximum load at failure is noted.
  • The load at failure shall be the maximum load at which the specimen fails to produce a further increase in the indicator reading on the testing machine.
  • The compressive strength of bricks is the ratio of maximum load at failure in N to the Area of the bed faces in mm^2. The average specimen is taken as compressive strength.
  • Minimum average compressive strength for various classes
Class DesignationAverage Compressive Strength not less than (N/mm^2)
3535
3030
2520
17.517.5
1515
12.512.5
1010
7.57.5
55
3.53.5
  • As per IS 1077-1976, bricks compressive strength shall not be less than 3.5 N/mm^2.

Read also:-

Leave a Reply

Your email address will not be published. Required fields are marked *