规范规定:评定混凝土强度等级应按立方体抗压强度标准值确定。也就是按标准养护边长为150mm的立方体试件在28d龄期,用标准试验方法测得的具有95％保证率的抗压强度,一般称为宏观试验。但是在下列情况下,须要在现场评定混凝土的强度等级,用以决定下一工序安排和对进一步测定混凝土强度等级提出参考意见:①对混凝土试件强度代表性有怀疑时;②混凝土试件留置数量 Specification stipulates: The assessment of concrete strength grade should be determined according to the cubic compressive strength standard value. That is, according to the standard, a cube specimen with a side length of 150 mm is cured at a 28-day age, and the compressive strength with a 95% guarantee ratio measured by a standard test method is generally called a macroscopic test. However, in the following cases, the strength grade of the concrete shall be evaluated in the field to determine the next process arrangement and provide reference opinions for further determination of the concrete strength grade: 1 When there is doubt about the representativeness of the strength of the concrete specimen; 2 The retention of concrete specimens Quantity