1.1本试验方法描述了近似最佳SO的测定 3. 在24小时、3天或7天时，通过测量因用硫酸钙代替部分水泥而在水硬性水泥砂浆中产生的强度变化，获得最大抗压强度。 1.2本试验方法适用于三氧化硫（SO 3. )仅水泥含量。矿渣水泥和偶尔的其他水硬性水泥可能含有硫化物或其他形式的硫。SO的测定 3. 快速方法的内容可能包括这些其他形式，因此可能会产生重大错误。如果出现重大错误，分析水泥的SO 3. 使用测试方法的参考测试方法的内容 C114 对于三氧化硫。 1.3以国际单位制表示的数值应视为标准值。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全和健康实践，并确定监管限制的适用性。 ====意义和用途====== 3.1本试验方法的目的是估计SO 3. 水硬性水泥的含量，在23°C下制成并固化的砂浆中提供最大抗压强度。获得的值是在规范中规定的水泥制造中确定适当硫酸盐水平的一种方法 C150 , C595 和 C1157 . 3.2 SO 3. 在不同的砂浆龄期，具有最大抗压强度的水泥含量不同；通常如此 3. 第3天的含量高于24小时，第7天的含量通常高于第3天。制造商可以选择24小时、3天或7天的试样龄期来确定最佳SO 3. 所容纳之物 3.3本试验方法表明最佳SO 3. 在23.0±2.0°C（73.5±3.5°F）的标准温度下制备和固化的砂浆中水泥的含量。最佳SO 3. 随温度升高而增加，使用减水剂时可能会增加。 3.4不应假设最佳值为 3. 本试验方法中的估计值与SO相同 3. 水泥制备的混凝土最佳性能的含量。 3.5本试验方法适用于规范中规定的水泥 C150 , C595 和 C1157 .

1.1 This test method describes the determination of approximate optimum SO 3 for maximum compressive strength at 24 h, 3 days, or 7 days by measuring the change in strength produced in hydraulic cement mortar as a result of substituting calcium sulfate for a portion of the cement. 1.2 This test method refers to the sulfur trioxide (SO 3 ) content of the cement only. Slag cements and occasionally other hydraulic cements can contain sulfide or other forms of sulfur. The determination of SO 3 content by rapid methods may include these other forms, and may therefore produce a significant error. If a significant error occurs, analyze the cement for SO 3 content using the reference test method of Test Methods C114 for sulfur trioxide. 1.3 Values stated as SI units are to be regarded as standard. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== 3.1 The purpose of this test method is to estimate the SO 3 content for a hydraulic cement that gives maximum compressive strength in mortar made and cured at 23 °C. The value obtained is one way to establish an appropriate level of sulfate in the manufacture of cements specified in Specifications C150 , C595 and C1157 . 3.2 The SO 3 content of a cement giving maximum compressive strength is different at different ages of mortar; typically this SO 3 content is higher at 3 days than the 24-h, and often higher for 7 days than that for 3 days. A manufacturer can choose the age of 24-h, 3 days or 7 days for specimens at which to determine optimum SO 3 content. 3.3 This test method indicates optimum SO 3 content for cement in mortar made and cured at a standard temperature of 23.0 ± 2.0 °C (73.5 ± 3.5 °F). The optimum SO 3 increases with increasing temperature and may increase when water-reducing admixtures are used. 3.4 It should not be assumed that the optimum SO 3 estimated in this test method is the same SO 3 content for optimum performance of a concrete prepared from the cement. 3.5 The test method is applicable to cements specified in Specifications C150 , C595 , and C1157 .