Acoustic absorption of conventional pavements

Traffic noise is a growing problem throughout the world. Pavement with a high acoustic absorption capability can significantly reduce the roadway traffic noise. The durability of such acoustically absorptive pavements is however major concern for the highway application. The sound absorption capabilities of typical portland cement concrete (PCC) that were surface textured in different configurations and typical asphalt concrete (AC) were measured in the Centre for Pavement and Transportation Technology (CPATT) laboratory at the University of Waterloo, Ontario (Canada) using a impedance tube and a custom designed portable reverberation chamber. On average, the regular 12.5 mm Superpave^TM (SP12.5), 12.5 mm stone mastic asphalt (SMA12.5) and the fine graded 12.5 mm Superpave^TM (SP12.5Fine) mixes were shown to absorb 6.3%, 7.5% and 8.5% of the sound energy, respectively. Textured PCC surfaces were shown to absorb 5% to 6% of the sound energy. The varying thickness has shown no significant effect on the variation of sound absorption of conventional dense AC and PCC pavements. The variation of bulk relative density (BRD) was shown to affect significantly the sound absorption capabilities of the AC pavements. However, the effect of the air voids content in the dense AC mixes was shown to be insignificant or minimal for the variation of sound energy absorption. Copyright @ Chinese Society of Pavement Engineering.