Question { UPPCL, 280662 }

How to calculate compressive strength of concrete?

Answer

Sample taken from the Concrete mix is First made into
required number of Cubes of nominal dimension (150 mm x 150
mm)and allowed to set for one day. The after removing the
sett cubes from the mould -after attaining final setting,
the cubes are then named with - Grade, Date of casting and
date of testing to be done and then put in curing tank.
Then required number of cubes are taken out on Seventh day
and tested in Compression testing Machine. and the same
process repeated after 28 days.
The Strength achieved is calculated as The Load at
Breakage/The Surface Area of the Cube.
For 7th day test the Strength achieved should be above 70%
of the Grade Strength of the Concrete and 28 th day should
be 120% of the Grade Strength.