How compressive strength of a concrete is determined?

To determine the compressive strength of concrete, 6 concrete samples are prepared using cube mould. Freshly prepared concrete is poured into 6 cube moulds and are kept for curing for 7 & 28 days. The preferred size of concrete cube used in concrete testing is 150mm x 150mm x 150mm. On 7th day, 3 concrete samples are extracted from their respective cube moulds and compression test is performed using compression machine. Similar process is repeated on 28th day with remaing 3 concrete cubes. 

When the force is applied on the concrete cube specimens, concrete starts to chip off and finally the specimen cracks. The force at which the specimen fails is noted and compressive strength of concrete cube is calculated. I.e, if the specimen cracks at 500kN force and size of specimen is 150 X 150 x 150 mm, the strength of cube will be (500 x 1000) / (150 x 150) N/sq. mm

Finally, the mean of all 6 concrete cube specimens, is used as the compressive strength of concrete.

Note: Only IS, BS or ASTM cube moulds should be used to prepare concrete samples, so as to maintain accuracy of test results.

To shorten the curing time, cube moulds can be kept in curing tank. Zeal International also supplies curing tanks to it’s customers. Click on the following links to know more about Curing Tank

or Cube Mould