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Two numbers giving crushing strength at twenty-eight days.
Also known as: Concrete class, C25/30
A concrete class such as C25/30 gives two crushing strengths in megapascals, measured on a cylinder and on a cube of the same mix. The pair is quoted because the two test shapes give systematically different results for identical concrete.
States a concrete's characteristic crushing strength in megapascals, measured at twenty-eight days.
Contexts: Technical drawing
Quotes two figures because cylinder and cube specimens give systematically different results from the same mix, and the pair identifies the class unambiguously.
Contexts: Technical drawing
A capital letter followed by two numerals separated by a slash, printed on a delivery ticket or drawing.