Answer: According to the strength of concrete, it is divided into 13 grades, namely C10, C15, C20, C25, C30, C35, C40, C45, C50, C55, C60, C70 and C80.
Its grade is based on the strength of the standard concrete test block after 28 days of standard curing, and is divided into one grade every 5MPa or 10MPa.
C is the first capital letter of the English word concrete, which means concrete, and the number in the corner indicates the strength grade.
