An increasing problem of modern times is the noise pollution due to tire/road noise caused by rising traffic density. Primary noise reduction strategies attempt to reduce the noise generation at the contact area of tire and road. Within the present work, the physical effects of the noise reduction of thin pavement layers were examined. Therefore, acoustical measurements according to ISO 11819-1 and measurements of the properties of the pavement (texture profiles, sound absorption coefficient and effective specific airflow resistance) were carried out at 14 measurement sites. For each of the pavements: AC 8, SMA 8, SMA/LA 8, DSK 5, DSH-V 5 and PMA 5, two measurement sites were chosen and investigated. All of them were in relatively new condition, meaning, that at the time of measurements they were not older than four years. The results of the acoustical measurements, show a very good agreement to values which can be found in literature. The highest noise reduction value of 6.3 dB was found on a DSH-V pavement. Comparing the properties of the pavement for each type of pavement, a specific characteristic can be found. Nevertheless, due to comparing the properties of the pavement with the results of the acoustical measurements, it was not possible to find a single parameter, to deduct the reduction of tire/road noise. However, the authors tried to give qualitative statements for the creation of low-noise pavements. Using the properties of the road surface as input parameters for the SPERoN model (Statistical Physical Explanation of Rolling Noise), the sound immission level next to the road was calculated for six different types of tires and then compared to the results of the acoustical measurements. For seven out of the 14 measurement sites, the agreement between measurement and calculation results was very good for all six tires. In four cases at least one tire showed a good agreement. In three cases the results for all six tires were out of bounds. The reason for the partially strong deviation could not be found within this research project. (Author/publisher)
Abstract