Correlation of axial compressive strength of concrete

The compressive strength of concrete includes the following three types:

1. Compressive strength of concrete cube: according to the national standard "Standard for Test Methods of Mechanical Properties of Ordinary Concrete" (GB/T5008 1-2002), cube specimens with side length of 150mm are made and cured under standard curing conditions (temperature 20 2℃, relative humidity not less than 95%).

2. Standard compressive strength of concrete cube (fcu, K): refers to the cube specimen with the side length of 150mm manufactured and maintained according to the standard method, and its compressive strength after 28 days is not less than 95% in the overall distribution of compressive strength measured by the standard test method. This value is commonly used, and its strength grades are divided into C 15, C20, C25, C30, C35, C40, C45, C50, C55, C60, C65, C70, C75 and C80 * *, where C50 represents the standard compressive strength of a concrete cube ≤50m pa FCU and ≤ K..

Three. Representative value of concrete compressive strength: take the average value of compressive strength of three specimens as the representative value. If the deviation between the maximum value or the minimum value and the average value is greater than 15%, the intermediate value is taken as the representative value; If the deviation between the maximum and minimum values and the average value is greater than 15%, the set of data is invalid.