1.1 本试验方法涵盖了使用圆形轨道仪（CT Meter）获取和分析路面宏观结构剖面的程序。 1.2 CT测量仪由一个电荷耦合器件（CCD）激光位移传感器组成，该传感器安装在旋转的臂上，使位移传感器沿着直径为284毫米的圆形轨道移动。 1.3 CT测量仪设计用于测量动态摩擦测试仪（DF测试仪）测量的相同圆形轨迹。 1.4 CT测量仪既可用于实验室调查，也可用于实际铺设表面的现场调查。 1.5 为CT Meter开发的软件报告宏观纹理剖面的平均剖面深度（MPD）和均方根（RMS）值。 1.6 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。 1.7 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 在PIARC国际实验中 ( 1. ) 4. 发现体积平均纹理深度（MTD）与国际摩擦指数的速度常数高度相关。已经发现，使用CT测量仪的八个节段的MPD值的平均值与MTD高度相关，并且可以代替体积测量来确定MTD ( 2. ) CT Meter根据MPD估算MTD的推荐关系为: 其中MTD和MPD以毫米表示。 注1: 这些方程式与实践中给出的方程式不同 E1845 ，用于从线性轮廓估计的纹理深度。 5.2 表面的MPD和RMS的比较提供了纹理性质的信息，即纹理是正的还是负的 ( 3. ) . 5.3 可以对各个分段进行分析，以检查平行于行进方向（分段A和E）和垂直于行进方向的剖面（分段C和G）。 这些信息在研究具有显著方向特征的纹理的表面时可能特别有用。

1.1 This test method covers the procedure for obtaining and analyzing pavement macrotexture profiles using the Circular Track Meter (CT Meter). 1.2 The CT Meter consists of a charge coupled device (CCD) laser-displacement sensor that is mounted on an arm that rotates such that the displacement sensor follows a circular track having a diameter of 284 mm. 1.3 The CT Meter is designed to measure the same circular track that is measured by the Dynamic Friction Tester (DF Tester). 1.4 The CT Meter can be used both for laboratory investigations and in the field on actual paved surfaces. 1.5 The software developed for the CT Meter reports the mean profile depth (MPD) and the root mean square (RMS) values of the macrotexture profiles. 1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this 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 ====== 5.1 In the PIARC International Experiment ( 1 ) 4 it was found that the volumetric mean texture depth (MTD) was highly correlated to the speed constant of the International Friction Index. It has been found that the average of the MPD values for the eight segments using the CT Meter is extremely highly correlated with the MTD and can replace the volumetric measurement for determination of the MTD ( 2 ) . The recommended relationship for the estimate of the MTD from the MPD by the CT Meter is: Where MTD and MPD are expressed in millimetres. Note 1: These equations differ from those given in Practice E1845 , which are for the estimated texture depths from linear profiles. 5.2 Comparison of the MPD and the RMS for a surface provides information of the nature of the texture, that is, whether the texture is positive or negative ( 3 ) . 5.3 Analysis of the individual segments can be performed to examine the profile parallel to the direction of travel (Segments A and E) and perpendicular to the direction of travel (Segments C and G). This information could be particularly useful in the study of surfaces that have texture with significant directional characteristics.