1.1 本试验方法描述了使用旋转轮试验机（RWT）测试沥青样品车辙和水敏感性的程序。Superpave旋转压实机（SGC）试样（试验方法 D6925 )包裹、调节、浸入水中，并限制在三个金属轮之间连续同步旋转，每个金属轮在试样周围施加固定载荷。系统记录施加到试样上的载荷循环次数、试样变形（车辙深度）、加载速率、水温和Sigma，Sigma是试样圆度的指标。 1.2 该试验方法通过测量车辙深度作为整个试验中荷载循环次数的函数来确定沥青混合料的早期车辙敏感性。 1.3 该试验方法还测量了水分损伤效应的可能性，因为在预处理期间和试验期间，试样浸没在温控水中。 1.4 测试参数如所示 表1 . 请参阅中使用的测试参数示例 附录X1 . 注1: 本试验使用Superpave旋转压实机生产的典型样本。 注2: 耐用性研究确定气孔含量是评估的最有影响的因素，并建议公差为±0.25 % 将空隙含量对试验结果的影响降至最低。精度研究评估了三种沥青混合料，试样空隙率为2。 87 % 至3.23 %, 从4.28开始 % 至4.64 %, 从5.77开始 % 至6.19 %. 精度声明涵盖2.75的空隙含量范围 % 至4.75 % 和5.75 % 至6.25 % 可在第节中找到 10 . Lemke和Bahia（2019）发现 % 与含3 % 空隙率和试验结果为7 % AV混合物没有区分控制因素，如测试温度和混合物来源，如含有3 % 空隙率没有。 注3: 威斯康星大学麦迪逊改性沥青研究中心（2017）报告称，洛杉矶市选择的测试温度为60℃ °C[140 °F]因为“( 1. )它近似于观察到的大多数路面的高平均温度( 2. )它接近大多数局部应用中使用的沥青结合料的高温性能等级分类( 3. )它允许在加速的时间范围内执行测试（约2 h不包括预处理时间），以及( 4. )车辙试验研究表明，在较低的试验温度下，沥青结合料似乎对试验结果具有最大的控制力。”耐久性研究在60岁时完成 °C[140 °F]使用PG 64-10和50 % RAC沥青混合料。精密度研究在60岁时完成 °C[140 °F]使用PG 64-10和50 % 使用第76页对两种混合物的RAC沥青混合料进行评估- 22用于考虑的第三种混合物。人们可能希望考虑降低试验温度，因为Lemke和Bahia（2019）报告将试验温度从60℃降低到60℃ °C[140 °F]至52 °C[125.6 °F]测试PG 58S-28和PG 58H-28沥青时，由于过早失效。 附注8 包括根据粘合剂选择替代试验温度的建议（如果选择这样做）。 注4: 威斯康星大学麦迪逊改性沥青研究中心（2017年）报告称，洛杉矶市选择6900个荷载循环作为最大荷载循环，因为“测试的初步观察结果表明，大多数测试样本的性能远远高于这些值（6900个荷载循环和6个荷载循环）。 0毫米[0.24英寸]）已实现。而那些在现场表现出较低车辙深度且没有水分敏感性的试验结果曲线表现为其初始蠕变斜率的渐近线，直到最大循环次数（30 000次循环）在坚固性和精度工作中也使用了6900个负载循环。机器的允许范围为300到30 000个负载循环。 注5: 威斯康星大学麦迪逊改性沥青研究中心（2017）报告称，洛杉矶市选择了6.0 mm[0.24] 在中。]作为最大车辙深度，因为“测试的初始观察结果表明，大多数测试样本在这些值之前表现出良好的性能（6900个负载循环和6个负载循环）。 0毫米[0.24英寸]）已实现。而那些在现场表现出较低车辙深度且没有水分敏感性的试验结果曲线表现为其初始蠕变斜率的渐近线，直到最大循环次数（30 000次循环）6.0毫米[0.24英寸]也用于坚固性和精密工作。 注6: 威斯康星大学麦迪逊改性沥青研究中心（2017年）报告称，洛杉矶市选择70 CPM作为加载速率，因为其RWT是由工厂设定的。70 CPM也用于坚固性和精度工作。机器的允许范围为60至90 CPM。 注7: 威斯康星大学麦迪逊改性沥青研究中心（2017年）报告称，洛杉矶市选择了334 N[75 lb]的外加荷载，因为这是工厂设定的RWT。334 N[75 lb]也用于坚固性和精度工作。机器的允许范围为334至489 N[75至110] 22-N[5-lb]增量。施加的载荷大于334 N[75 根据经验，不建议使用lb]。 1.5 应根据当地条件和材料特性制定测试结果的评估和解释标准。 附录X1 显示了如何使用和解释测试结果的示例。 1.6 本试验方法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（不包括表和图中的注释和脚注）不应视为试验方法的要求。 1.7 单位- 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是精确的等效值；因此，每个系统应相互独立使用。将两个系统的值合并可能会导致不符合标准。 1.8 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。 1.9 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====== 4.1 该试验方法用于测定沥青混合料的车辙敏感性和水敏感性。车辙和抗湿损性有助于区分使用寿命可能因永久变形或湿损而受损的混合物。该测试方法适用于在60±0℃下测试的试样。 5. °C[140±0.9 °F]。试样几何形状的直径为150 毫米[5.9英寸]高度为115±5 mm[4.5±0.2 in]。使用Superpave旋转压实机制备试样。 注9: 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 D3666 通常认为能够胜任和客观的测试、抽样、检查等。本标准的用户应注意遵守规范 D3666 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； 遵循规范建议 D3666 或一些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 describes a procedure for testing the rutting and moisture susceptibility of asphalt specimens using the Rotary Wheel Tester (RWT). Superpave Gyratory Compactor (SGC) specimens (Test Method D6925 ) are wrapped, conditioned, submerged in water, and confined between three metal wheels in continuous synchronized rotation with each wheel applying a fixed load around the periphery of the specimen. The system records the number of load cycles applied to the specimen, the deformation of the specimen (rut depth), the loading rate, the temperature of the water, and Sigma, which is an indication of specimen roundness. 1.2 The test method is used to determine the premature rutting susceptibility of asphalt mixtures by measuring rut depth as a function of number of load cycles throughout the test. 1.3 This test method also measures the potential for moisture damage effects because the specimens are submerged in temperature-controlled water during preconditioning and for the duration of the test. 1.4 The parameters of the test are shown in Table 1 . See an example of the test parameters used in Appendix X1 . Note 1: This test uses a typical specimen produced by a Superpave gyratory compactor. Note 2: The ruggedness study identified air void content as the most influential factor evaluated and recommended a tolerance of ±0.25 % to minimize the effect of air void content on the test results. The precision study evaluated three asphalt mixtures with specimen air void contents ranging from 2.87 % to 3.23 %, from 4.28 % to 4.64 %, and from 5.77 % to 6.19 %. Precision statements covering the air void content ranges of 2.75 % to 4.75 % and 5.75 % to 6.25 % can be found in Section 10 . Lemke and Bahia (2019) found that an asphalt mixture with 7 % air void content was more susceptible to rutting than a mixture with 3 % air void content and that the test results for the 7 % AV mixture did not differentiate between control factors such as test temperature and mixture source like the mixture with 3 % air void content did. Note 3: The University of Wisconsin at Madison Modified Asphalt Research Center (2017) reported that the City of LA selected the test temperature of 60 °C [140 °F] because “( 1 ) it approximates the observed high average temperature of most pavements, ( 2 ) it is close to the high temperature performance grade classification of the asphalt binder used in most local applications, ( 3 ) it allows a test to be performed in an accelerated time frame (about 2 h excluding preconditioning time), and ( 4 ) research on rut testing has shown [that] the asphalt binder seems to have the most control over the test results at lower test temperatures.” The ruggedness study was completed at 60 °C [140 °F] using PG 64-10 with 50 % RAC asphalt mixture. The precision study was completed at 60 °C [140 °F] using PG 64-10 with 50 % RAC asphalt mixture for two of the mixtures evaluated and using PG 76-22 for the third mixture considered. One may wish to consider lower test temperatures because Lemke and Bahia (2019) reported reducing the test temperature from 60 °C [140 °F] to 52 °C [125.6 °F] when testing PG 58S-28 and PG 58H-28 asphalt because of premature failure. Note 8 includes a suggestion for selecting an alternative test temperature based on the binder if one chooses to do so. Note 4: The University of Wisconsin at Madison Modified Asphalt Research Center (2017) reported that the City of LA selected 6900 load cycles as the maximum load cycles because “initial observations from tests showed that most samples tested showed their performance well before these values (6900 load cycles and 6.0 mm [0.24 in.]) were attained. while those that exhibited low rut depth in the field and no moisture susceptibility showed test result curves that behaved as asymptotes to their initial creep slope until the maximum number of cycles (30 000 cycles) of the machine was attained.” 6900 load cycles was used in both the ruggedness and precision work as well. The machine has an allowable range of 300 to 30 000 load cycles. Note 5: The University of Wisconsin at Madison Modified Asphalt Research Center (2017) reported that the City of LA selected 6.0 mm [0.24 in.] as the maximum rut depth because “initial observations from tests showed that most samples tested showed their performance well before these values (6900 load cycles and 6.0 mm [0.24 in.]) were attained. while those that exhibited low rut depth in the field and no moisture susceptibility showed test result curves that behaved as asymptotes to their initial creep slope until the maximum number of cycles (30 000 cycles) of the machine was attained.” 6.0 mm [0.24 in.] was used in both the ruggedness and precision work as well. Note 6: The University of Wisconsin at Madison Modified Asphalt Research Center (2017) reported that the City of LA selected 70 CPM as the loading rate because that is what its RWT was set at by the factory. 70 CPM was used in both the ruggedness and precision work as well. The machine has an allowable range of 60 to 90 CPM. Note 7: The University of Wisconsin at Madison Modified Asphalt Research Center (2017) reported that the City of LA selected an applied load of 334 N [75 lb] because that is what its RWT was set at by the factory. 334 N [75 lb] was used in both the ruggedness and precision work as well. The machine has an allowable range of 334 to 489 N [75 to 110 lb] in 22-N [5-lb] increments. Applied loads of greater than 334 N [75 lb] are not recommended based on experience. 1.5 Criteria for the evaluation and interpretation of test results shall be developed for local conditions and material characteristics. Appendix X1 shows an example of how test results are used and interpreted. 1.6 The text of this test method 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 test method. 1.7 Units— 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. 1.8 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. 1.9 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 The test method is developed for determining the rutting and moisture susceptibility of asphalt mixtures. The rutting and moisture damage resistance can help differentiate mixtures whose service life might be compromised by permanent deformation or by moisture damage. The test method is valid for specimens that are tested at temperatures of 60 ± 0.5 °C [140 ± 0.9 °F]. Test specimen geometry is a diameter of 150 mm [5.9 in.] and a height of 115 ± 5 mm [4.5 ± 0.2 in.]. Specimens are prepared using a Superpave gyratory compactor. Note 9: 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.