1.1 本试验方法涵盖了使用实验室制备的圆柱形沥青混合料样品或路面芯制备、测试和测量沥青混合料抗裂性的程序。测试温度从长期路面性能（LTPP）数据库中间温度中选择。试验方法描述了裂纹容限指数的测定， 计算机断层扫描 指数 ，以及根据荷载-位移曲线确定的其他参数。这些参数可用于评估沥青混合料的抗裂性。 1.2 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.3 本标准的文本引用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）不应视为本标准的要求。 1.4 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。 1.5 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 间接拉伸开裂试验用于确定沥青混合料在中间温度下的抗裂性，中间温度范围为5 °C至35 °C，取决于当地气候。试样很容易从直径为150±2 mm的Superpave回转压实机压实圆柱体中获得，无需切割、粘合、开槽、钻孔或仪器。同样，可以测试现场岩心，以测量就地沥青混合料的剩余抗裂性。 5.2 这个 计算机断层扫描 指数 根据破坏能、荷载-位移曲线的峰后斜率和75%峰值荷载下的变形公差计算沥青混合料的变形。这个 计算机断层扫描 指数 是包含各种沥青粘合剂、沥青粘合剂改性剂、骨料混合物、纤维和再生材料的沥青混合料抗裂性的性能指标。 一般来说，温度越高 计算机断层扫描 指数 值，则抗裂性越好，因此，现场开裂量越小。可接受的范围 计算机断层扫描 指数 将随混合类型和相关的具体应用而变化。 4. 用户可以使用 计算机断层扫描 指数 以及在配合比设计和生产质量控制/保证期间识别易开裂混合物的相关标准。 注1: 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 covers the procedures for preparing, testing, and measuring asphalt mixture cracking resistance using cylindrical laboratory-prepared asphalt mix samples or pavement cores. Testing temperatures are selected from the long-term pavement performance (LTPP) database intermediate temperatures. The test method describes the determination of the cracking tolerance index, CT Index , and other parameters determined from the load-displacement curve. These parameters can be used to evaluate the resistance of asphalt mixtures to cracking. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 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. 1.4 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. 1.5 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 The indirect tensile cracking test is used to determine asphalt mixture cracking resistance at an intermediate temperature which could range from 5 °C to 35 °C, depending on local climate. The specimens are readily obtained from Superpave gyratory compactor compacted cylinders with a diameter of 150 ± 2 mm, with no cutting, gluing, notching, drilling, or instrumentation required. Similarly, field cores can be tested to measure remaining cracking resistance of in-place asphalt mixtures. 5.2 The CT Index of an asphalt mixture is calculated from the failure energy, the post-peak slope of the load-displacement curve, and deformation tolerance at 75 % of the peak load. The CT Index is a performance indicator of the cracking resistance of asphalt mixtures containing various asphalt binders, asphalt binder modifiers, aggregate blends, fibers, and recycled materials. Generally, the higher the CT Index value, the better the cracking resistance and, consequently, the less the cracking amount in the field. The range for an acceptable CT Index will vary with mix types and associated specific applications. 4 Users can employ the CT Index and associated criteria to identify crack-prone mixtures during mix design and production quality control/assurance. Note 1: 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.