# Concrete Compressive Strength

Hi, as the compressive strength of concrete formula is max load applied/ surface area, could you say that the compressive strength of concrete is inversely proportional to it's surface area or this would make no sense as the concrete with a smaller surface would have a smaller max load anyway and hence the compressive strength of concrete for a certain mixture will always be roughly the same, thanks for any help!

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A fairly typical concrete mix will support around 4,000 psi, with micro fiber reinforcement and admix chemicals different mixes can achieve far higher strengths, allowing them to do the job, using far less space. Some of the concrete for example in the WTC freedom tower is rated @ 60,000 psi, or a 1 inch cube could hold up 60,000 pounds if the force is applied evenly to one face, and the footing of the cube is strong enough. Using a 4,000 psi formula you would need to displace that force over 15 square inches.

Chestermiller
Mentor
Hi, as the compressive strength of concrete formula is max load applied/ surface area, could you say that the compressive strength of concrete is inversely proportional to it's surface area or this would make no sense as the concrete with a smaller surface would have a smaller max load anyway and hence the compressive strength of concrete for a certain mixture will always be roughly the same, thanks for any help!
Yes, the latter.