普通硅酸盐水泥、火山灰质硅酸盐水泥、矿渣硅酸盐水泥的标准是在1956年制訂的。按标准规定水泥标号必須由3、7、28天三个龄期的强度来确定,而事实上很多水泥厂都等不及得出28天結果水泥就出厂;施工部門,一般也不等得出28天强度結果,就要使用。为了又快又准地确定水泥标号,保証工程质量,避免水泥浪費,我們首先参照以下公式,根据3、7天强度推算28天强度。 The standards for ordinary portland cement, pozzolanic portland cement, and slag portland cement were formulated in 1956. According to the standard, the cement number must be determined by the strength of 3, 7, 28 days and 3 years of age. In fact, many cement plants can’t wait to get the 28-day result and the cement goes to the factory; the construction department generally does not wait to get 28 The day intensity result is used. In order to determine the cement label quickly and quasily, ensure the quality of the project, and avoid cement waste, we first calculate the strength for 28 days based on the strengths of 3 and 7 days by referring to the following formula.