ASTM E2157-15(2019)

5.1 In the PIARC International Experiment Where MTD and MPD are expressed in millimetres.

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.

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.