1.1 本试验方法旨在用作快速现场相关性试验。本试验方法的目的是在标准条件下，指示通过4.75 mm（4号）筛的粒状土壤和细骨料中粘土粒径或塑性细粒和粉尘的相对比例。“砂当量”一词表达了这样一个概念，即大多数粒状土壤和一些细骨料是理想的粗颗粒、砂粒大小的颗粒以及通常不理想的粘土或塑料细粒和灰尘的混合物。 注1: 对于含有干净断裂粉尘（非粘土矿物的粘土粒度颗粒）的细骨料，试验结果将取决于材料中存在的细骨料数量。在这种情况下，可能需要进行亚甲基蓝值（AASHTO T 330）或X射线衍射（XRD）等其他测试，以确定细骨料是否有害。 注2: 一些机构对顶部尺寸小于4.75 mm（编号。 4） 筛子。这样做是为了避免在片状4.75至2.36 mm（4号至8号）大小的颗粒下方截留粘土或塑料细粒和灰尘。测试较小的顶级材料可能会降低测试的数值结果。 1.2 以英寸-磅单位表示的数值视为标准值。括号中给出的值是数学转换为SI单位，仅供参考，不被视为标准单位。 1.2.1 关于筛子，按照规范 E11号机组 第1.3小节，“以国际单位表示的数值应视为筛布开口尺寸和筛布中使用的钢丝直径的标准值。以英寸-磅单位表示的值应视为关于筛框、盘和盖的标准值”。当参考筛目尺寸时，备用英寸-磅名称仅供参考，并用括号括起来。 1.3 本标准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（表和图中的除外）不应视为本标准的要求。 1.4 本标准并不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。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）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====== 5.1 本试验方法为试样中存在的类粘土材料的相对数量、细度和特性指定了一个经验值。 5.2 可规定最小砂当量值，以限制允许的粘土量- 骨料中的类似或粘土大小的细粒。 5.3 该试验方法为确定生产或浇筑期间骨料质量的变化提供了一种快速现场方法。 注3: 本标准产生的结果的质量取决于执行程序的人员的能力以及所用设备的能力、校准和维护。符合规范标准的机构 D3666美元 通常认为能够胜任客观的测试、取样、检验等。本标准的用户应注意遵守规范 D3666美元 单独使用并不能完全确保结果的可靠性。可靠的结果取决于许多因素；遵循规范建议 D3666美元 或类似的可接受指南提供了评估和控制其中一些因素的方法。

1.1 This test method is intended to serve as a rapid field correlation test. The purpose of this test method is to indicate, under standard conditions, the relative proportions of clay-size or plastic fines and dust in granular soils and fine aggregates that pass the 4.75 mm (No. 4) sieve. The term “sand equivalent” expresses the concept that most granular soils and some fine aggregates are mixtures of desirable coarse particles, sand-size particles, and generally undesirable clay or plastic fines and dust. Note 1: For fine aggregates containing clean dust of fracture (clay-size particles that are not clay minerals), test results will depend on the amount of fines present in the material. In this case, other tests such as Methylene Blue Value (AASHTO T 330) or X-ray diffraction (XRD) may be needed to determine if the fines are deleterious. Note 2: Some agencies perform the test on material with a top size smaller than the 4.75 mm (No. 4) sieve. This is done to avoid trapping the clay-size or plastic fines and dust below flaky shaped 4.75 to 2.36 mm (No. 4 to 8) sized particles. Testing smaller top sized material may lower the numerical results of the test. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.2.1 Regarding sieves, per Specification E11 subsection 1.3, “the values stated in SI units shall be considered standard for the dimensions of the sieve cloth openings and the wire diameter used in the sieve cloth. The values stated in inch-pound units shall be considered standard with regard to the sieve frames, pans, and covers.” When sieve mesh sizes are referenced, the alternate inch-pound designations are provided for information purposes and enclosed in parentheses. 1.3 The text of this standard 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 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 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 ====== 5.1 This test method assigns an empirical value to the relative amount, fineness, and character of clay-like material present in the test specimen. 5.2 A minimum sand equivalent value may be specified to limit the permissible quantity of clay-like or clay-size fines in an aggregate. 5.3 This test method provides a rapid field method for determining changes in the quality of aggregates during production or placement. Note 3: The quality of the results produced by this standard are dependent upon the competence of the personnel performing the procedure and the capability, calibration, and the maintenance of the equipment used. Agencies that meet the criteria of Specification D3666 are generally considered capable of competent and objective testing, sampling, inspection, etc. Users of this standard are cautioned that compliance with Specification D3666 alone does not completely ensure reliable results. Reliable results depend on many factors; following the suggestions of Specification D3666 or similar acceptable guideline provides a means of evaluating and controlling some of those factors.