1.1 本试验方法旨在作为快速现场相关性试验。本试验方法的目的是在标准条件下，表明通过4.75-mm（4号）筛的粒状土壤和细骨料中粘土粒径或塑性细颗粒和灰尘的相对比例。术语“砂当量”表示的概念是，大多数粒状土壤和一些细骨料是理想的粗颗粒、砂粒级颗粒以及通常不理想的粘土或塑料细颗粒和灰尘的混合物。 注1: 对于含有清洁断裂粉尘（非粘土矿物的粘土大小颗粒）的细骨料，测试结果将取决于材料中存在的细粒量。 在这种情况下，可能需要进行其他测试，如亚甲基蓝值（AASHTO T330）或X射线衍射（XRD），以确定细粒是否有害。 注2: 一些机构对顶部尺寸小于4.75 mm（4号）筛的材料进行试验。这样做是为了避免将粘土大小或塑料细颗粒和灰尘捕集在片状4.75至2.36 mm（4至8号）大小的颗粒以下。测试较小顶部尺寸的材料可能会降低测试的数值结果。 1.2 以英寸-磅为单位的数值应视为标准值。括号中给出的值是到国际单位制的数学转换，仅供参考，不被视为标准值。 1.2.1 关于筛子，根据规范 E11 第1.2节，“以国际单位制表示的数值应视为钢丝网开口尺寸和钢丝网中使用的钢丝直径的标准值。以英寸磅为单位表示的数值应视为筛框的标准值。”当参考筛孔尺寸时，提供备用英寸-磅名称以供参考，并将其括在括号中。 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。 ====意义和用途====== 5.1 该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 可以规定最小砂当量值，以限制骨料中粘土状或粘土大小的细粒的允许数量。 5.3 该试验方法提供了一种快速现场方法，用于确定生产或放置过程中骨料质量的变化。 注3: 本标准产生的结果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。符合实践标准的机构 D3666 通常认为能够胜任和客观的测试/采样/检查等。本标准的用户应注意遵守惯例 D3666 单独使用并不能完全保证结果的可靠性。可靠的结果取决于许多因素:遵循实践建议 D3666 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 T330) 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 Section 1.2, “the values stated in SI units shall be considered standard for the dimensions of the wire cloth openings and the diameter of the wires used in the wire cloth. The values stated in inchpound units shall be considered standard with regard to the sieve frames.” When sieve mesh sizes are referenced, the alternate inch-pound designations are provided for information purposes and enclosed 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 and health practices and determine the applicability of regulatory limitations prior to use. ====== Significance And Use ====== 5.1 This test method assigns an empirical value to the relative amount, fineness, and character of claylike material present in the test specimen. 5.2 A minimum sand equivalent value may be specified to limit the permissible quantity of claylike 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 dependant 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 Practice D3666 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3666 alone does not completely assure reliable results. Reliable results depend on many factors: following the suggestions of Practice D3666 or similar acceptable guideline provides a means of evaluating and controlling some of those factors.