1.1 这些方法通过比色技术测定施工中使用的粘性土壤的水溶性硫酸盐含量。本标准中提出了两种方法。方法A用于现场，方法B用于实验室。比色技术包括测量光束通过含有悬浮颗粒物的溶液的散射。建筑土壤中硫酸盐浓度的测量可用于指导专业人员选择适当的稳定方法，并有助于评估混凝土结构的潜在劣化。 注1: 这些测试方法部分基于德克萨斯州A & M大学。 1.2 现场法，即方法A，用于筛选硫酸盐的存在及其浓度。实验室方法B提供了比现场方法更好的分辨率。 1.3 离子色谱法也是一种可接受的替代方法，可用于评估结果，但它不在本标准的范围内。 1.4 单位- 以国际单位制表示的数值应视为标准。本标准不包括其他计量单位。 1.5 所有观测值和计算值应符合实践中制定的有效数字和四舍五入指南 D6026型 ，除非被本试验方法取代。 1.5.1 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。所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；并且通常的做法是增加或减少报告数据的有效数字以与这些考虑相称。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。 1.6 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。 1.7 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。 ====意义和用途====== 5.1 如果怀疑存在硫酸盐，应将路基土壤作为岩土工程评估的一个组成部分进行测试，因为如果使用含钙稳定剂来改善土壤，则可能会发生硫酸盐引起的隆起，硫酸盐反应也可能导致混凝土结构劣化。当计划用石灰处理施工中使用的土壤时，在处理前测试土壤中的水溶性硫酸盐变得非常重要( 注释2 ). 5.2 当用钙基稳定剂处理含硫酸盐的粘性土壤以改善地基时，天然土壤中的硫酸盐和游离氧化铝与钙和游离氢氧化物反应，形成结晶矿物，如钙矾石和钙矾石。 4. 钙矾石是在低温下，钙矾石在碳酸盐的存在下发生变化时形成的。 5. 硫酸盐矿物在水合时会显著膨胀。 注2: 有关处理含有水溶性硫酸盐的土壤效果的更多信息，请参阅以下出版物:Little，D.N.，《用石灰稳定路面路基和基层》，Kendal/HuntPublishing Co.，Dubuque，IA，1995。 注3: 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 第3740页 通常被认为能够进行合格且客观的测试/取样/检查等。本标准的使用者应注意遵守实践 第3740页 这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 第3740页 提供了一种评估其中一些因素的方法。

1.1 These methods determine the water soluble sulfate content of cohesive soils used in construction by using the colorimetric technique. Two methods are presented in this standard. Method A is for use in the field and Method B is for use in the laboratory. The colorimetric technique involves measuring the scattering of a light beam through a solution that contains suspended particulate matter. Measurements of sulfate concentrations in construction soils can be used to guide professionals in the selection of appropriate stabilization methods and to assist in assessment of potential deterioration in concrete structures. Note 1: These test methods are partially based on the research conducted by Texas A & M University. 1.2 The field method, Method A, is used as a screening test for the presence of sulfates and their concentration. The laboratory method, Method B, provides better resolution than the field method. 1.3 Ion chromatography is also an acceptable alternative method that can be used to evaluate results, however, it is outside the scope of this standard. 1.4 Units— The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 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. 1.5.1 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. 1.6 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. 1.7 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. ====== Significance And Use ====== 5.1 Where sulfates are suspected, subgrade soils should be tested as an integral part of a geotechnical evaluation because the possibility that sulfate induced heave may occur if calcium containing stabilizers are used to improve the soils and sulfate reactions may also cause deterioration in concrete structures. When planning to treat a soil used in construction with lime, testing the soil for water soluble sulfates prior to treatment becomes very important ( Note 2 ). 5.2 When sulfate containing cohesive soils are treated with calcium-based stabilizers for foundation improvements, sulfates and free alumina in natural soils react with calcium and free hydroxide to form crystalline minerals, such as ettringite and thaumasite. 4 Thaumasite forms when ettringite undergoes changes in the presence of carbonates at low temperatures. 5 The sulfate minerals expand considerably when they are hydrated. Note 2: For more information on the effect of treating soils containing water soluble sulfates, refer to the following publication: Little, D.N., Stabilization of Pavement Subgrades and Base Course with Lime, Kendal/Hunt Publishing Co., Dubuque, IA, 1995. Note 3: 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.