Concrete strength measured using concrete cubes produce results different than concrete cylinders. Conservative estimates put concrete cylinders at 80% of concrete cubes, for high-strength concrete some say the percentage is near 100%.
The ratio between the cube(150mm) and cylindrical sample(150×300 mm).
Generally Strength of Cylinder sample= 0.8 x Strength of Cube.
Example:- M20 is equivalent to C25
C25 is 1:1:3
(1 part cement, 1 part fine aggregate, and 3 parts coarse aggregate.)
whereas C25 symbolizes a Cylindrical sample in which cement, fine aggregates, coarse aggregates are mixed in such a ratio that its characteristic compressive strength is 25 N/mm^2 after 28 days of curing.
M 20 is 1:1.5:3
whereas M20 symbolizes a Cubic sample in which cement, fine aggregates, coarse aggregates are mixed in such a ratio that its characteristic compressive strength is 20 N/mm^2 after 28 days of curing.
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