Ali, A., Khalid, M., Adulateef, A., Mahmoud, R. (2025). Plastic roads: evaluating the role of waste PET in hot mix asphalt – a review. , 43(11), 879-890. doi: 10.30684/etj.2025.159983.1956
Anwer M. Ali; Mustafa Q. Khalid; Ahmed D. Adulateef; Rasha K. Mahmoud. "Plastic roads: evaluating the role of waste PET in hot mix asphalt – a review". , 43, 11, 2025, 879-890. doi: 10.30684/etj.2025.159983.1956
Ali, A., Khalid, M., Adulateef, A., Mahmoud, R. (2025). 'Plastic roads: evaluating the role of waste PET in hot mix asphalt – a review', , 43(11), pp. 879-890. doi: 10.30684/etj.2025.159983.1956
Ali, A., Khalid, M., Adulateef, A., Mahmoud, R. Plastic roads: evaluating the role of waste PET in hot mix asphalt – a review. , 2025; 43(11): 879-890. doi: 10.30684/etj.2025.159983.1956

Plastic roads: evaluating the role of waste PET in hot mix asphalt – a review

Engineering and Technology Journal
Volume 43, Issue 11, November 2025, Pages 879-890    PDF (782.09 K)
Document Type: Review Paper
DOI: 10.30684/etj.2025.159983.1956
Authors
Anwer M. Ali* 1; Mustafa Q. Khalid2; Ahmed D. Adulateef1; Rasha K. Mahmoud2
1Department of Civil Engineering, University of Samarra, 34010 Samarra, Iraq.
2College of Engineering, University of Baghdad- Iraq, Al Jadriya, 10071 Baghdad, Iraq.
Abstract
Plastic pollution has become a global environmental crisis, with millions of tons of polyethylene terephthalate (PET) waste accumulating in landfills and ecosystems. One promising solution is the integration of waste PET into hot-mix asphalt (HMA), offering the dual benefits of sustainable waste management and enhanced pavement performance. This review critically examines the mechanical, environmental, and economic impacts of PET-modified asphalt. Studies indicate that PET improves rutting resistance, durability, and flexibility, with optimal performance observed at moderate PET dosages (4– 6%). However, excessive PET content (> 6%) can lead to stiffening and premature cracking, while very high PET concentrations (> 20%) may reduce load-bearing capacity. Beyond mechanical benefits, the incorporation of PET significantly reduces carbon emissions and energy consumption, with Life Cycle Assessment (LCA) studies reporting a 47.4% reduction in Global Warming Potential (GWP). Economic analyses indicate that PET-modified asphalt can reduce bitumen consumption, resulting in potential cost savings; however, processing and collection costs remain significant barriers to the large-scale adoption of this technology. Despite promising laboratory results, long-term field trials remain limited, and concerns about phase separation, regulatory approval, and large-scale feasibility hinder widespread implementation. Future research should focus on long-term field evaluations, optimization of PET processing methods, and the development of standardized industry guidelines. Additionally, hybrid polymer modifications and multi-polymer blends should be explored to enhance performance and sustainability. With continued innovation and policy support, PET-modified asphalt presents a viable pathway toward greener and more durable road infrastructure.

Highlights
  • PET-modified asphalt enhances rutting resistance, stability, and fatigue life at a dosage of 4–6%
  • Wet and dry mixing techniques have a significant influence on mechanical performance and moisture resistance
  • A Life Cycle Assessment (LCA) reveals a potential reduction of up to 47.4% in Global Warming Potential using PET
  • Fine particle PET enhances dispersion and interfacial bonding while reducing permanent deformation
  • Economic feasibility improves when PET replaces bitumen, resulting in lower material and maintenance costs
Keywords
PET waste; Hot mix asphalt; Rutting resistance; Sustainability; Plastic recycling; Road construction
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