ASTM E1845-01(2005)e1

This practice is suitable for the calculation of the average macrotexture depth from profile data. The results of this calculation (MPD) have proven to be useful in the prediction of the speed dependence of wet pavement friction.²

The MPD can be used to estimate the result of a measurement of macrotexture depth using a volumetric technique according to E 965. The values of MPD and MTD differ due to the finite size of the glass spheres used in the volumetric technique and because the MPD is derived from a two-dimensional profile rather than a three-dimensional surface. Therefore a transformation equation must be used.

This practice may be used with pavement macrotexture profiles taken on actual road surfaces or from cores or laboratory prepared samples.

Aggregate size, shape, and distribution are features which are not addressed in this practice. This practice is not meant to provide a complete assessment of texture characteristics. In particular, care should be used when interpreting the result for porous or grooved surfaces.

This practice does not address the problems associated with obtaining a measured profile. Laser or other optical noncontact methods of measuring profiles are usually preferred. However, contact methods using a stylus also can provide accurate profiles if properly performed.

1.1 This practice covers the calculation of mean profile depth from a profile of pavement macrotexture.

1.2 The mean profile depth has been shown to be useful in predicting the speed constant (gradient) of wet pavement friction.

1.3 A linear transformation of the mean profile depth can provide an estimate of the mean texture depth measured according to Test Method E 965.

1.4 The values stated in SI (metric) units are to be regarded as standard. The inch-pound equivalents are rationalized, rather than exact mathematical conversions.

1.5 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 and health practices and determine the applicability of regulatory limitations prior to use.