4 Different types of Tests on Bricks | crushing strength absorption

Different Types of Tests on Bricks

The following laboratory strength tests methods are all may be conducted on the bricks to find their suitability:

 

1.Crushing strength

2.Absorption

3.Shape and size and

4.Efflorescence.

Crushing Strength.

strength



  • The brick specimen is immersed in water for 24 hours (strength). The frog of the brick is filled flush with 1:3 cement mortar and the specimen is stored in a damp jute bag for 24 hours and then immersed in clean water for 24 hours. The specimen is placed in a compression testing machine with 6 mm plywood on top and bottom of it to get the uniform load on the specimen.
  • Then the load is applied axially at a uniform rate of 14 N/mm2. The crushing load is noted. After the crushing strength test is the ratio of the crushing load to the area of bricks are loaded. Average of five specimens are taken as the crushing strength.

Absorption Test:

  • The brick specimen is weighed dry (strength).
  • Then they are immersed in water for a period of 24 hours. The specimen is taken out and wiped with a cloth. The weight of each specimen in a wet condition is determined. The difference in weight indicates the water absorbed.
  • After the percentage (%) of absorption is the ratio of the water absorbed to dry weight multiplied by 100(hundred). The average of five specimens is taken. This value should not exceed 20 per cent.

 

Shape and Size:

  • The Bricks should be of basic size and edges should be a truly rectangular shape with sharp edges. To check it, 20 bricks are selected at random and they are stacked along the length, along the width and then along with the height. For the standard bricks of size 190-millimetre × 90 millimetres × 90 millimetres (strength).

IS code permits the following limits:

 Lengthwise: 3680 to 3920 mm

 Widthwise: 1740 to 1860 mm
Height wise: 1740 to 1860 mm.

 

 

 

The following fields are tests help to find out the good quality bricks (strength):

  • uniformity in size
  • uniformity in colour
  • structure
  • hardness test
  • sound test
  • strength test.
  • Uniformity in Size

 



  • A good brick should have a rectangular plane surface and uniform in size. This checking is made in all field by in observation(strength).
  • Uniformity in Colour: A good brick will be having a uniform colour throughout. This checking may be done before purchasing the bricks.
  • Structure: A some bricks are may be broken in the type and their cross-section was observed. The section should be similar, compress, and free from defects such as holes and combine.
  • Sound Test: If two bricks are struck with each other they should produce a clear ringing sound. The sound should not be dull.
  • Hardness Test: For this, a simple field test is a scratch the brick with the nail. Maybe impression is marked top of the surface, the brick is enough hard

Efflorescence:

  • The presence of alkalis in brick is not desirable because they form patches of Gray powder by absorbing moisture. Hence to determine the presence of alkalis this test is performed as explained below.
  • Place of the brick specimen in a glass dish containing water to a depth of 25millimetres in a well-ventilated room. After all the water is absorbed or evaporated again add water for a depth of 25 millimetres.
  • After the second evaporation observes the bricks for white/grey patches.

(a) Nil: No patches

(b) Slight: 10% of the area covered with deposits

(c) Moderate: 10 to 50% area covered with a deposit but unaccompanied by flaking of the surface.

(d) Heavy: This is More than 50 per cent area covered with accumulation but unattended by flaking of the surface.

(e) Serious: This is Heavy accumulation of salt accumulation by flaking of the surface.