Standard Test Method for Measuring Pavement Macrotexture Properties Using the Circular Track Meter

Abstract

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.