Through the surface roughness analysis and the use of silicone replicas

• Silicone replicas can accurately reproduce certain road surface textures. • Bitumen in voids improves replica accuracy, while porous roads show large errors. • Roughness and PSD highlight differences between silicone and real surfaces. Direct topographic profiling of real pavement surfaces is often challenging, especially on high-traffic highways or racetracks where access time is limited. In such cases, silicone replicas offer a practical alternative for acquiring detailed surface information related to frictional behavior, wear mechanisms, and the mechanical response of materials in contact. In this work, a quantitative comparison is presented between topographic measurements carried out on two road specimens and the corresponding silicone replicas produced via dedicated molding, alongside methodological guidelines for the correct use of silicone replicas and the processing of the acquired topographic data. 3D areal parameters according to ISO 25178-2, such as the power spectral density (PSD), the probability density function (PDF), and the Abbott–Firestone curve, are compared between the silicone replica and the drill road surface to validate whether the replica can reliably reproduce the surface information. The comparison between silicone and the road specimens underlines that the technique must be employed with care, since differences attributable to “mushroom-shaped” cavities can lead to considerable errors in the roughness parameters.