For determination of compressive strength of bricks 

Reference Standard

IS: 3495 – P (1)-1992-Methods of tests of burnt clay building bricks (Determination of compressive strength)

Equipment & Apparatus

  • Compression Testing Machine
  • Scale for measuring dimension of brick


  1. Unevenness observed in the bed faces of bricks is removed to provide two smooth and parallel faces by grinding. It is immersed in water at room temperature for 24 h.
  2. The specimen is then removed and any surplus moisture is drained out at room temperature. The frog and all voids in the bed face is filled with cement mortar (1 cement, clean coarse sand of grade 3 mm and down). It is stored under the damp jute bags for 24 h followed by immersion in clean water for 3 days.
  3. The specimen is placed with flat faces horizontal, and mortar filled face facing upwards between two 3 ply plywood sheets each of 3 mm thickness and carefully centered between plates of testing machine.
  4. Load is applied axially at a uniform rate of 14 N/mm2 per minute till failure occurs. The maximum load at failure is noted down. The load at failure is considered the maximum load at which the specimen fails to produce any further increase in the indicator reading on the testing machine. 


Brick compressive strength 1


Five number of bricks should be tested and the average value is reported.

Safety & Precautions

  • Safety shoes should be used at the time of testing.
  • Before testing, CTM machine should be properly checked.

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