ASTM E2157-15 (R2019) PDF Download

The ASTM E2157-15 (R2019) standard provides guidelines for obtaining and analyzing pavement macrotexture profiles using the Circular Track Meter (CT Meter). This test method offers a standardized approach for measuring pavement texture depth, which is an important factor in evaluating road safety and friction characteristics.

The CT Meter is equipped with a charge coupled device (CCD) laser-displacement sensor mounted on an arm that rotates along a circular track with a diameter of 284 mm. This measurement device allows for consistent and accurate data collection both in the laboratory and in the field on actual paved surfaces. The software associated with the CT Meter provides data on the mean profile depth (MPD) and root mean square (RMS) values of the macrotexture profiles.

The standard highlights the correlation between the MPD values obtained using the CT Meter and the volumetric mean texture depth (MTD). This correlation has been demonstrated in previous studies, indicating that the CT Meter can be used as an alternative to the more time-consuming volumetric measurements for MTD determination.

Additionally, the standard suggests that comparing the MPD and RMS values can provide insights into the nature of the pavement texture, distinguishing between positive and negative texture characteristics.

Furthermore, the standard acknowledges that analysis of individual segments, specifically those parallel and perpendicular to the direction of travel, can be useful in studying surfaces with significant directional characteristics.

It is important to note that the equations provided in this standard for estimating the MTD from the MPD differ from those given in Practice E1845, which are for estimating texture depths from linear profiles.