Analysis of Tyre Rolling Noise on Low Noise Pavements

In this work, the relationship between Tyre-Road Noise (TRN) and road surface properties, such as road texture, Mean Profile Depth (MPD) and enveloped texture was studied from an experimental point of view. TRN was measured using the CPX method. The first step consisted in providing a model of the sound pressure field inside the tyre cavity using analytical calculations and a Finite Element Method (FEM) simulation, both in agreement with experimental measurements. These measurements were performed with a Tyre Cavity Noise (TCN) sensor, which was then used on-field to study the relationship between TCN and superficial properties of low noise pavements. Results show that noise inside the tyre cavity is greatly affected by road surface characteristics at frequencies below 1 kHz. The second step consisted in the study of the correlation between TRN outside emission and road texture. Results show that two indicators of TRN can be derived: a low frequency indicator and a high frequency indicator. The correlation between outside noise and cavity noise reveals that the two fields are similar at low frequency, but a model cannot be obtained with a straightforward approach, due to the intrinsic differences between the physical quantities. At last, models for forecasting the initial CPX levels from the Job Mix Formula and the acoustic ageing of low noise surfaces using traffic load, weather and pavement conditions were developed.