1.1 本规程涵盖了使用真空干燥设备干燥压实沥青混合料试样的过程。 1.2 通过这种方法干燥的试样保持在室温下，这有助于在干燥过程中保持试样的完整性。 1.3 本规程可用于压实的圆柱形、立方体实验室和现场沥青混合料试样。 1.4 该做法也可用于干燥其他建筑材料，如混凝土、土壤、骨料和松散沥青混合物。使用制造商的建议干燥其他建筑材料。 1.5 以国际单位制或英寸磅单位表示的数值应单独视为标准值。每个系统中规定的值可能不完全相等； 因此，每个系统应独立使用。将两个系统的值合并可能导致不符合标准。 1.6 本标准的文本引用了提供说明材料的注释和脚注。这些注释和脚注（不包括表和图中的注释和脚注）不应视为本标准的要求。 1.7 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建立适当的安全、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《国际标准、指南和建议制定原则决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 4.1 在建筑和原材料行业中，试样干重是确定准确密度和许多其他测试的关键指标。某些测试需要在室温下干燥试样，这为其他测试提供了确保完整性和保持试样特性的优势。 4.2 本规程包括在真空室中干燥压实的沥青混合料试样，该真空室能够将试样保持在接近室温的温度。真空泵降低了室内的压力，从而使水在低温下蒸发。由于试样在蒸发过程中自然冷却，使水更难蒸发，因此必须在室内进行适当的温度控制，以确保试样保持在接近室温的温度。 装置内的自动控制通过周期性地允许通常由在线空气加热器产生的热空气和干燥空气流进入真空室，使试样保持在接近室温的温度。在真空和气流条件之间循环可以使试样在短时间内干燥。保留水超过30 g[0.07 lb]的完全饱和试样可在约30分钟内干燥。对于大多数未完全饱和的现场岩芯，干燥时间通常小于15 最小值。 注1: 循环时间（周期）取决于材料成分。每个循环包括30至180秒的真空操作和30至120秒的气流的交替周期。 4.3 该方法可用于直径100 mm[4 in.]、150 mm[6 in.]。 ]直径圆柱形和立方体压实沥青混合料试样。 4.4 该方法也可用于干燥松散沥青混合料、骨料样品和其他固体试样。除压实沥青混合料试样外，应遵循制造商推荐的干燥试样程序。 4.5 该方法可用于通过在干燥操作前后称量样品来确定干燥过程中的水分含量和水分损失量。 注2: 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。符合规范标准的机构 第3666页 通常认为能够胜任和客观的测试、取样、检验等。 本标准的用户应注意遵守规范 第3666页 单独使用并不能完全确保可靠的结果。可靠的结果取决于许多因素；遵循规范的建议 第3666页 或一些类似的可接受准则提供了评估和控制这些因素的方法。

1.1 This practice covers the process of drying compacted asphalt mixture specimens using vacuum drying apparatus. 1.2 The specimens dried by this practice remain at room temperature, which helps in maintaining specimen integrity during the drying process. 1.3 This practice can be used for compacted cylindrical and cubical laboratory and field asphalt mixture specimens. 1.4 This practice can also be used for drying other construction materials such as concrete, soils, aggregates, and loose asphalt mixtures. Use the manufacturer’s recommendations for drying other construction materials. 1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard. 1.6 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. 1.7 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 ====== 4.1 Specimen dry weight is a critical measure in determination of accurate density and many other tests in the construction and raw materials industries. Drying specimens at room temperature is required for some tests and provides an advantage for other tests to ensure the integrity and to preserve the characteristics of specimens. 4.2 This practice covers drying compacted asphalt mixture specimens in a vacuum chamber that is capable of keeping the specimen at close to room temperature. A vacuum pump reduces the pressure inside the chamber, thus allowing water to evaporate at low temperature. Since the specimen naturally cools during the evaporation process, making water harder to evaporate, it is important to have proper temperature controls in the chamber to ensure the specimen remains at close to room temperature. Automatic controls within the unit allow the specimen to remain at close to room temperature by periodically allowing a flow of warm and dry air, typically generated by an inline air heater, to enter the vacuum chamber. Cycling between vacuum and airflow conditions allows the specimen to dry in a short period of time. Completely saturated specimens with over 30 g [0.07 lb] of retained water can be dried in about 30 min. For most field cores that are not completely saturated, the drying time is generally less than 15 min. Note 1: Cycle time (period) can depend on the material composition. Each cycle involves an alternating period of 30 to 180 s of vacuum operation and 30 to 120 s of airflow. 4.3 This method can be used for 100 mm [4 in.] diameter, 150 mm [6 in.] diameter cylindrical, and cubical compacted asphalt mixture specimens. 4.4 This method can also be used for drying loose asphalt mixtures, aggregate samples, and other solid specimens. Follow the manufacturer’s recommended procedures for drying specimens other than compacted asphalt mixture specimens. 4.5 This method can be used to determine moisture content and amount of water loss during drying by weighing the sample before and after the drying operations. Note 2: The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and 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 some similar acceptable guideline provides a means of evaluating and controlling some of those factors.