1.1 本试验方法涵盖固体材料真实比重的测定，特别适用于不适合用试验方法进行试验的易水合材料 C135 .本试验方法可用作试验方法的替代方法 C135 ， C128 和 C188 用于确定真实比重。 1.2 单位-- 以国际单位制表示的数值应视为标准。本标准中不包括其他计量单位。 1.2.1 例外-- 在里面 7.3 ，等效国际单位制用括号表示。 1.3 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.4 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ===意义和用途====== 4.1 材料的真实比重是在特定温度下确定的其真实密度与在特定温度下水的真实密度的比值。因此，材料的真实比重是与化学和矿物学组成有关的主要性质。 4.2 该试验方法对不适合用试验方法进行试验的可水合材料特别有用 C135 。 4.3 对于耐火材料原料和产品，真实比重是一个有用的值，用于:分类、检测假定相似样品之间的化学成分差异、指示矿物学相或相变、在已知堆积密度时计算总孔隙率，以及用于计算结果时需要该值的任何其他测试方法。 4.4 该测试方法是一种主要的标准方法，适用于规范、质量控制和研发。它也可以作为采购合同或协议中的裁判测试方法。 4.5 该测试方法固有的基本假设如下: 4.5.1 样品通常代表材料， 4.5.2 总样品已经减少到指定的颗粒尺寸， 4.5.3 在样品的处理过程中没有引入污染， 4.5.4 样品的点燃消除了所有游离的或结合的水，而没有引起烧结或改变， 4.5.5 试验中使用了惰性气体（氦气），并且 4.5.6 试验方法进行得很细致。 4.5.7 偏离这些假设中的任何一个都会否定结果的有用性。 4.6 在解释该试验方法的结果时，必须认识到指定的样品颗粒尺寸明显比试验方法规定的要细 C135 即使样品的这种更细的颗粒尺寸也不排除存在一些闭孔，并且残余闭孔的量可以在不同材料之间或者甚至在相同或相似材料的样品之间变化。因此，这种测试方法产生的值可能是非常接近的近似值，而不是真实比重的准确表示。因此，只有在通过该测试方法测试的类似材料之间，或者在充分认识到被比较的材料或所使用的测试方法之间潜在的固有差异的情况下，才能明智地对结果进行比较。

1.1 This test method covers the determination of the true specific gravity of solid materials, and is particularly useful for materials that easily hydrate which are not suitable for test with Test Method C135 . This test method may be used as an alternate for Test Methods C135 , C128 , and C188 for determining true specific gravity. 1.2 Units— The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.2.1 Exception— In 7.3 , the equivalent SI unit is expressed in parentheses. 1.3 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 The true specific gravity of a material is the ratio of its true density, determined at a specific temperature, to the true density of water, determined at a specific temperature. Thus, the true specific gravity of a material is a primary property which is related to chemical and mineralogical composition. 4.2 This test method is particularly useful for hydratable materials that are not suitable for test with Test Method C135 . 4.3 For refractory raw materials and products, the true specific gravity is a useful value for: classification, detecting differences in chemical composition between supposedly like samples, indicating mineralogical phases or phase changes, calculating total porosity when the bulk density is known, and for any other test method that requires this value for the calculation of results. 4.4 This test method is a primary standard method which is suitable for use in specifications, quality control, and research and development. It can also serve as a referee test method in purchasing contracts or agreements. 4.5 Fundamental assumptions inherent in this test method are the following: 4.5.1 The sample is representative of the material in general, 4.5.2 The total sample has been reduced to the particle size specified, 4.5.3 No contamination has been introduced during processing of the sample, 4.5.4 The ignition of the sample has eliminated all free or combined water without inducing sintering or alteration, 4.5.5 An inert gas (helium) has been used in the test, and 4.5.6 The test method has been conducted in a meticulous manner. 4.5.7 Deviation from any of these assumptions negates the usefulness of the results. 4.6 In interpreting the results of this test method, it must be recognized that the specified sample particle size is significantly finer than specified for Test Method C135 . Even this finer particle size for the sample does not preclude the presence of some closed pores, and the amount of residual closed pores may vary between materials or even between samples of the same or like materials. The values generated by this test method may, therefore, be very close approximations rather than accurate representations of true specific gravities. Thus, comparisons of results should only be judiciously made between like materials tested by this test method or with full recognition of potentially inherent differences between the materials being compared or the test method used.