In concrete compression test, normally 150mmx150mmx150mm concrete cube samples is used for testing. Why isn’t 100mmx100mmx100mm concrete cube samples used in the test instead of 150mmx150mmx150mm concrete cube samples?

In   concrete   compression   test,   normally   150mmx150mmx150mm   concrete   cube samples is used for testing. Why isn’t 100mmx100mmx100mm concrete cube samples used in the test instead of 150mmx150mmx150mm concrete cube samples?
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1 Answer

Answer :

Basically, the force supplied by a concrete compression machine is a definite value. For normal   concrete   strength   application,   say   below   50MPa,   the   stress   produced   by   a 150mmx150mmx150mm cube is sufficient for the machine to crush the concrete sample. However,   if   the   designed   concrete   strength   is   100MPa,   under   the   same   force   (about 2,000kN) supplied by the machine, the stress under a 150mmx150mmx150mm cube is not sufficient to crush the concrete cube. Therefore, 100mmx100mmx100mm concrete cubes are used instead to increase the applied stress to crush the concrete cubes. For   normal   concrete   strength,   the   cube   size   of   150mmx150mmx150mm   is   already sufficient for the crushing strength of the machine.
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