我国混凝土标号是用边长为20厘米的立方试块,在标准条件下养护到28天所测得的极限抗压强度来确定的。但在混凝土的设计和施工中,混凝土的后期强度,特别是60天和90天龄期的混凝土强度往往被人忽略,没有加以合理的利用,因此开展对混凝土后期 The concrete marking in China is determined by using a cubic test piece with a side length of 20 cm and curing under standard conditions until the ultimate compressive strength measured in 28 days. However, in the design and construction of concrete, the concrete’s later strength, especially the 60-day and 90-day-old concrete strengths, are often neglected and not reasonably used. Therefore, the later stage of the concrete construction