1.1 本规范涵盖了用作化学掺合料的材料，这些材料将添加到水硬性水泥混凝土混合物中，用于以下八种类型的用途: 1.1.1 A型-- 减水剂， 1.1.2 B类-- 缓凝剂， 1.1.3 C类-- 加速外加剂， 1.1.4 D型-- 减水剂和缓凝剂， 1.1.5 E类-- 减水剂和速凝剂， 1.1.6 F型-- 减水剂、高掺量外加剂， 1.1.7 G型-- 减水剂、高掺量和缓凝剂，以及 1.1.8 S型-- 特定性能外加剂。 1.2 除非买方另有规定，否则用于鉴定掺合料的试样应使用混凝土浇筑材料制成，如 11.1 – 11.3 . 注1: 如文中所述 附录X2 ，建议买方在可行的情况下使用水泥、火山灰、骨料、空气进行补充试验- 掺合料，以及为特定工程提出的混合比例、配料顺序和其他物理条件，因为化学掺合料产生的具体影响可能因混凝土其他成分的性质和比例而异。例如，在水泥含量高于表1所列的混凝土混合物中，F和G型外加剂可能表现出更高的减水率 12.1.1 . 注2: 买方应验证工程中使用的外加剂在成分上与根据本规范进行测试的外加剂相等（见第 6. 一致性和等效性）。 注3: 含有足够量氯化物的外加剂可能会加速钢筋的腐蚀。遵守本规范的要求并不构成对钢筋混凝土中使用的外加剂可接受性的保证。 1.3 本规范规定了三个级别的测试。 1.3.1 级别1-- 在初始批准阶段，证明符合中定义的性能要求 表1 证明外加剂符合本规范的要求。合规性证明应基于对各批试验混凝土的平均试验结果与各批参考混凝土的平均测试结果的比较。如果凝固时间、长度变化和耐久性系数符合物理要求和括号中所示的任何替代抗压强度要求，则外加剂（B、C、E和S类除外）应符合临时合规要求 表1 在临时验收日期之前满足（见 附注4 ). 如果六个月后的后续测试结果不符合至少100%参考强度的要求，则该外加剂暂时不符合本标准，并应立即通知所有外加剂使用者。 截面均匀性和等效性试验 6. 应进行测试，以提供结果，以便以后进行比较。 注4: 允许临时合规性，同时保持长期抗压强度要求，可以促进新材料的更快鉴定，但也可以保证新的外加剂技术不会表现出意想不到的长期性能。替代抗压强度要求 表1 基于对规范的统计分析 C494/C494M 评估测试。括号中所示的替代要求对应于在后续测试年龄通过强度要求的99%的概率， 2. 如果满足任何一个要求。没有要求满足所有要求。 1.3.2 2级-- 有限的重新测试在 5.2 – 5.2.2 符合以下要求的证明 表1 证明外加剂持续符合规范要求。 1.3.3 级别3-- 对于批次的验收或批次内或批次之间的均匀性测量，如果买方有规定，则应进行第节的均匀性和等效性测试 6. 应使用。 1.4 以国际单位制或英寸-磅单位表示的值应单独视为标准值。每个系统中所述的值不一定是完全等效的；因此，为确保符合标准，每个系统应独立使用，两个系统的值不得组合。有些值只有国际单位制，因为实践中没有使用英寸-磅当量。 1.5 本标准的文本是指提供解释性材料的注释和脚注。这些注释和脚注（不包括表格和图表中的注释和脚注）不应被视为本标准的要求。 1.6 以下预防性警告仅适用于测试方法章节 11 – 18 本规范中: 本标准并不旨在解决与其使用相关的所有安全问题（如果有的话）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。 ( 警告-- 新鲜的水硬性水泥混合物具有腐蚀性，长时间接触可能会对暴露的皮肤和组织造成化学灼伤。 3. ) 1.7 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。

1.1 This specification covers materials for use as chemical admixtures to be added to hydraulic-cement concrete mixtures for the purpose or purposes indicated for the eight types as follows: 1.1.1 Type A— Water-reducing admixtures, 1.1.2 Type B— Retarding admixtures, 1.1.3 Type C— Accelerating admixtures, 1.1.4 Type D— Water-reducing and retarding admixtures, 1.1.5 Type E— Water-reducing and accelerating admixtures, 1.1.6 Type F— Water-reducing, high range admixtures, 1.1.7 Type G— Water-reducing, high range, and retarding admixtures, and 1.1.8 Type S— Specific performance admixtures. 1.2 Unless specified otherwise by the purchaser, test specimens for qualifying an admixture shall be made using concreting materials as described in 11.1 – 11.3 . Note 1: As discussed in Appendix X2 , it is recommended that, whenever practicable, supplementary tests be made by the purchaser using the cement, pozzolan, aggregates, air-entraining admixture, and the mixture proportions, batching sequence, and other physical conditions proposed for the specific work because the specific effects produced by chemical admixtures may vary with the properties and proportions of the other ingredients of the concrete. For example, Types F and G admixtures may exhibit much higher water reduction in concrete mixtures having higher cement contents than that listed in 12.1.1 . Note 2: The purchaser should verify that the admixture supplied for use in the work is equivalent in composition to the admixture subjected to test under this specification (see Section 6 , Uniformity and Equivalence). Note 3: Admixtures that contain sufficient amounts of chloride may accelerate corrosion of steel reinforcement. Compliance with the requirements of this specification does not constitute assurance of acceptability of the admixture for use in reinforced concrete. 1.3 This specification provides for three levels of testing. 1.3.1 Level 1— During the initial approval stage, proof of compliance with the performance requirements defined in Table 1 demonstrates that the admixture meets the requirements of this specification. Proof of compliance shall be based on comparisons of the average test results from the batches of test concrete and the average test results from the batches of reference concrete. Admixtures (except for Types B, C, E, and S) shall qualify for provisional compliance if the time of setting, length change, and durability factor meet the physical requirements and any of the alternative compressive strength requirements shown in parentheses in Table 1 are met through the date of provisional acceptance (see Note 4 ). If subsequent test results at six months fail to meet the requirement of at least 100 % of reference strength, the provisional compliance of the admixture to this standard is withdrawn and all users of the admixture shall be notified immediately. Uniformity and equivalence tests of Section 6 shall be carried out to provide results against which later comparisons shall be made. Note 4: Allowing for provisional compliance while retaining longer term compressive strength requirements promotes more rapid qualification of new materials, but also provides assurance that new admixture technologies will not exhibit unexpected longer term performance. The alternative compressive strength requirements in Table 1 are based on statistical analysis of Specification C494/C494M evaluation tests. The alternative requirements shown in parentheses correspond to a 99 % probability of passing strength requirements at subsequent test ages, 2 if any one of the requirements is met. There is no requirement that all be met. 1.3.2 Level 2— Limited retesting is described in 5.2 – 5.2.2 . Proof of compliance with the requirements of Table 1 demonstrates continued conformity of the admixture with the requirements of the specification. 1.3.3 Level 3— For acceptance of a lot or for measuring uniformity within or between lots, if specified by the purchaser, the uniformity and equivalence tests of Section 6 shall be used. 1.4 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined. Some values have only SI units because the inch-pound equivalents are not used in practice. 1.5 The text of this standard refers to notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard. 1.6 The following precautionary caveat pertains only to test method Sections 11 – 18 of this Specification: 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. ( Warning— Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to exposed skin and tissue upon prolonged exposure. 3 ) 1.7 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.