Sound absorption capacity of hot and warm asphaltic mixes modified with waste plastic bottles

Abstract

Vehicular traffic is one of the noise-producing factors contributing to environmental problems. Utilizing special asphaltic mixes can help reduce noise generation. Thus, this research evaluated the sound absorption capacity (SAC) of hot mixed asphalt (HMA) and warm mixed asphalt (WMA) modified with pyrolyzed polyethylene terephthalate (PET) bottles varying at 1-17 wt. %. PET bottles were pyrolyzed at 450 °C for a 2 h retention period, obtaining pyrolyzed PET bottle (PTB). HMA and WMA were prepared with 0-17 wt. % PTB and the SAC values were tested. The results were compared to a control mix, a standard HMA or WMA without any PTB modification, to provide a baseline for the evaluation. The effects of volumetric and Marshall properties of HMA and WMA on SAC were correlated. The results revealed decreased sound levels with increasing PTB dosage in the HMA. However, WMA generated increased sound levels as PTB content increased from 1-9 wt. % but decreased after 9 wt. % of PTB substitution. HMA and WMA performed best at 11 and 7 wt. % PTB with corresponding SAC values of 78.23 and 80.53 dB compared to the control mix with 79.33 dB.