(1)P The following clauses give principles and rules for normal and high strength concrete.
(2)P Rules for lightweight aggregate concrete are given in Section 11.
(1) The compressive strength of concrete is denoted by concrete strength classes which relate to the characteristic (5%) cylinder strength fck, or the cube strength fck,cube, in accordance with EN 206-1.
(2) The strength classes in this code are based on the characteristic cylinder strength fck determined at 28 days with a maximum value of Cmax.
Note: The value of Cmax for use in a Country may be found in its National Annex. The recommended value is C90/105.