1.1本试验方法描述了最佳SO的测定 3. 通过测量水硬性水泥砂浆中因用硫酸钙代替部分水泥而产生的强度变化，获得最大24小时抗压强度。通常，但并非总是如此 3. 在23°C下产生最高24小时强度的含量在该温度下也会在水中产生最低的膨胀，在空气中产生最低的收缩。 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. 含量采用试验方法C 114中的三氧化硫参考试验方法。 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。

1.1 This test method describes the determination of optimum SO 3 for maximum 24-h compressive strength by measuring the change in strength produced in hydraulic cement mortar as a result of substituting calcium sulfate for a portion of the cement. Usually, but not always, the SO 3 content that produces the highest 24-h strength at 23°C also produces approximately the lowest expansion in water and the lowest contraction in air at that temperature. 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 C 114 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.