人的认识在不断实践中,从未停止在一个平面上,并力图以新的认识指导混凝土技术的发展。上世纪的40年代后,随着水泥工业和混凝土技术的发展,人们发现水泥标号或强度不同,也应是混凝土抗压强度不可忽视的另一重要影响因素。90年代后随着对混凝土耐久性的重视,矿物掺合料的普遍应用,人们总是力图以新的形式对混凝土强度做新的表达。这是B公式发展演变的必然规律,没有改变的是对随机变量的数理统计原理。 People’s understanding in constant practice, never stop in a plane, and trying to guide the development of concrete technology with new understanding. After the 40s of the last century, with the development of cement industry and concrete technology, it was found that the different grades or intensities of cement should also be another important factor that can not be ignored in compressive strength of concrete. After the 1990s, with the emphasis on the durability of concrete, the universal application of mineral admixtures, people always try to make a new form of new expression of concrete strength. This is the inevitable law of the evolution of formula B, what has not changed is the principle of mathematical statistics of random variables.