1.1 本试验方法使用pH计测量接收到的颗粒材料的pH值，代表现场用于路堤、路基和挡土墙回填的材料。试验方法的主要用途是补充土壤电阻率测量，以确定嵌入颗粒材料或与颗粒材料接触的金属腐蚀可能急剧加剧的条件。 1.2 颗粒材料的pH值通常由机构规定，以满足必要的标准，以防止或减少路堤、路基和挡土墙回填中使用的颗粒材料中嵌入的金属物体的腐蚀。 1.3 可使用本标准测试pH值的颗粒材料类型为天然或人造粗砂、天然或碎石、天然或碎砾石、风冷高炉炉渣和骨料:轻、重或正常重量。根据AASHTO M 145，这些颗粒材料通常属于AASHTO分类组A-1、A-2-4、A-2-5或A-3。理想的材料是级配良好的自由排水材料，其含水量小于10-15 % 通过75μm（200号）筛。 1.4 本试验基于体积法，因为填充材料的单位重量将因来源和项目规范而异。 1.5 单位- 以国际单位制表示的数值应视为标准值。除筛网名称外，根据规范使用“替代”系统对其进行识别 E11 ，例如3英寸。和第200号，而不是分别为75 mm和75µm的“标准”。本标准不包括其他计量单位。以国际单位制以外的单位报告试验结果不应视为不符合本标准。 1.6 所有观察值和计算值应符合实践中确定的有效数字和舍入准则 D6026 ，除非被本试验方法取代。 1.6.1 用于规定如何在标准中收集/记录和计算数据的程序被视为行业标准。此外，它们代表了通常应保留的有效数字。使用的程序不考虑材料变化、获取数据的目的、特殊目的研究或用户目标的任何考虑因素；通常的做法是增加或减少报告数据的有效位数，以与这些考虑因素相称。考虑工程数据分析方法中使用的有效数字超出了这些测试方法的范围。 1.7 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、健康和环境实践，并确定监管限制的适用性。 1.8 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 路堤、路基和挡土墙回填中使用的颗粒材料通常必须符合与腐蚀电位有关的某些规范，例如pH值和电阻率。本标准用于材料制造商、供应商和接收者测量材料的pH值，以供其预期用途验收。 5.2 挡土墙制造商通常使用类似于:100的颗粒材料规格 % 通过100毫米（4英寸）筛，75-100 % 通过75毫米（3英寸）筛，0-15 % 通过75μm（200号）筛。 规格可能因当地材料的可用性而异。 5.3 由于受试材料的总表面积会影响试验结果，因此样品和试样的级配必须与指定或拟议使用的材料相同。不允许通过破碎来减小粒度，因为该过程可能会改变材料的pH值，并且可能无法代表实际放置在现场的材料。 注1: 本标准产生的结果的质量取决于执行该标准的人员的能力，以及所用设备和设施的适用性。 符合实践标准的机构 D3740 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 D3740 本身并不能保证可靠的结果。可靠的结果取决于许多因素；实践 D3740 提供了一种评估其中一些因素的方法。

1.1 This test method uses a pH meter to measure the pH of as-received granular material that represents what will be used in the field for embankments, subgrades, and retaining wall backfill applications. The principal use of the test method is to supplement soil resistivity measurements to identify conditions under which the corrosion of metal embedded in granular material, or in contact with the granular material may be sharply accentuated. 1.2 The pH of granular material is often specified by agencies to meet criteria that are necessary to prevent or reduce corrosion of metal objects embedded in the granular material used in embankments, subgrade, and retaining wall backfill. 1.3 The types of granular material that can be tested for pH using this standard are natural or manufactured coarse sand, natural or crushed stone, natural or crushed gravel, air-cooled blast furnace slag, and aggregates: lightweight, heavyweight, or normal weight. According to AASHTO M 145, these granular materials generally fall into AASHTO classification groups A-1, A-2-4, A-2-5, or A-3. The ideal material is a well-graded, free draining material that has less than 10-15 % passing the 75 μm (No. 200) sieve. 1.4 This test is based on the volumetric method because the unit weight of the fill material will vary depending on source and project specifications. 1.5 Units— The values stated in SI units are to be regarded as standard. Except the sieve designations, they are identified using the “alternative” system in accordance with Specification E11 , such as 3 in. and No. 200, instead of the “standard” of 75 mm and 75 µm, respectively. No other units of measurement are included in this standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard. 1.6 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026 , unless superseded by this test method. 1.6.1 The procedures used to specify how data are collected/recorded and calculated in the standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of these test methods to consider significant digits used in analysis methods for engineering data. 1.7 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. 1.8 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 Granular material being used in embankments, subgrades, and retaining wall backfill must often meet certain specifications relating to corrosion potential, such as pH and electrical resistivity. This standard is used by manufacturers, suppliers, and recipients of the materials to measure the pH of the material for acceptance for its intended use. 5.2 Retaining wall manufactures often use a granular material specification similar to: 100 % passing the 100 mm (4 in.) sieve, 75-100 % passing the 75 mm (3 in.) sieve, and 0-15 % passing the 75 μm (No. 200) sieve. The specification may vary depending on availability of local materials. 5.3 Since the total surface area of the material being tested affects the test results, the sample and specimen must have the same grading as the material specified or proposed for use. Reducing the particle size by crushing is not permitted since this process may alter the pH of the material and will likely not be representative of the material actually being placed in the field. Note 1: The quality of the result produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.