NF ISO 13473-4, S31-252-4 (05/2024)

This document describes the methods available for performing a spectral analysis of a pavement surface profile. It defines a method for analyzing the spatial frequency (or texture wavelength) of two-dimensional surface profiles that describe the texture amplitude of a road surface as a function of distance along a trajectory straight or curved on the roadway. It also describes another method (not preferred) to obtain these spectra: a) constant relative bandwidth obtained by digital filtering (normative method); b) fine-band frequency analysis using a discrete Fourier transform (DFT), followed by a transformation of the fine-band spectrum into an octave or third-octave band spectrum (informative method). The result of the frequency analysis will be a spatial frequency (or texture wavelength) spectrum in constant percentage octave or third octave bands. The objective of this document is to standardize the spectral characterization of pavement surface profiles. To achieve this objective, a detailed description of the analysis methods and associated requirements is provided for those who are involved in the characterization of road surfaces but who are unfamiliar with the general principles of frequency analysis of random signals. These methods and requirements generally apply to all types of random signals; however, they are discussed in detail in this document for their use in surface profile analysis of road surfaces. NOTE The spectral analysis as specified in this document cannot express all the characteristics of the surface profile studied. In particular, the effects of profile asymmetry, for example the difference in certain functional properties for "positive" and "negative" profiles, cannot be expressed by the power spectral density since it abstracts from any signal asymmetry (see Annex B).
(Automatic translation from French)