1.1 该分类定义了粗骨料的机械筛分分析的骨料尺寸编号和标准尺寸范围，以及用于各种类型公路和桥梁的施工和维护的筛分。 1.2 单位- 以国际单位表示的值应视为标准值。本标准不包括其他计量单位。 注1: 筛孔尺寸由规范中的标准名称确定 第11页 括号中给出的备选名称仅供参考，并不代表不同的标准筛号。 1.3 本分类的文本参考了提供解释材料的注释和脚注。这些注释和脚注（不包括表格和图表中的注释）不应视为分类要求。 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》中确立的国际公认标准化原则制定的。 =====意义和用途====== 4.1 一些合同文件规定了特定用途的特定骨料尺寸，或可能建议一种或多种适合制备各种最终产品混合物的骨料尺寸。在某些情况下，需要对骨料级配的可变性进行更严格的限制。

1.1 This classification defines aggregate size number designations and standard size ranges for mechanical sieve analyses of coarse aggregate and screenings for use in the construction and maintenance of various types of highways and bridges. 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. Note 1: Sieve size is identified by its standard designation in Specification E11 . The alternative designation given in parentheses is for information only and does not represent a different standard sieve size. 1.3 The text of this classification references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the classification. 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 Some contract documents specify certain aggregate sizes for specific uses or may suggest one or more of these sizes as appropriate for the preparation of various end-product mixtures. In some cases, closer limits on variability of the aggregate grading are required.