2026-10-13 ペンシルベニア州立大学（PennState）
＜関連情報＞
- https://www.psu.edu/news/research/story/recycled-plastic-asphalt-may-boost-pavement-performance-limit-particle-release
- https://www.sciencedirect.com/science/article/abs/pii/S0959652626020123
再生プラスチック改質アスファルトからのマイクロプラスチック放出：検出、特性評価、および環境への影響 Microplastics release from recycled plastic modified asphalt: Detection, characterization, and environmental implications
Zhen Liu, Hlengilizwe Nyoni, Odette Mina, Shihui Shen
Journal of Cleaner Production Available online: 14 September 2026
DOI:https://doi.org/10.1016/j.jclepro.2026.149471
Highlights
- Microplastics release from RPMA mixtures is quantitatively assessed via LDIR imaging.
- A normalized particle area (NPA) index is proposed to evaluate microplastic release levels.
- RPMA show less LDPE release potential than unmodified asphalt under laboratory testing conditions.
Abstract
Recycled Plastic-Modified Asphalt (RPMA) has gained increasing attention in pavement engineering for its dual potential to reduce plastic waste and enhance pavement performance. Despite this growing interest, previous research and practical applications have focused mainly on engineering performance, with limited attention to the potential release of microplastics during pavement service life. This unresolved issue is environmentally important because released particles may enter surrounding soil, water, and air. Therefore, this study aimed to explore experimental methodologies to evaluate microplastic release from RPMA mixtures and their individual components under simulated environmental and traffic loading conditions. Using Laser Direct Infrared Imaging (LDIR), a vibrational spectroscopy technique that combines the surface sensitivity of attenuated total reflectance (ATR) with high-throughput, spatially resolved detection, spectra resembling low-density polyethylene (LDPE) were identified in asphalt binder and asphalt mixtures. This suggests that the inherent asphalt components may complicate microplastic source attribution, particularly after stress and environmental exposure. To quantify the release potential of RPMA, an apparent normalized particle area (NPA) index was proposed. Results showed that RPMA mixtures maintained greater structural integrity than unmodified mixtures under the tested laboratory conditions. Based on all particles tentatively identified as LDPE-like by LDIR, RPMA exhibited an apparent NPA that was 56.5% lower than that of the unmodified asphalt after combined high-temperature and moisture-conditioning. Although based on limited experiments, these preliminary findings highlight both the potential environmental trade-offs and the benefits of RPMA, demonstrate the utility of ATR-LDIR in differentiating polymeric sources, and underscore the need for standardized methods to assess microplastic releases from infrastructural pavement materials.
