Evaluating the Curing Effects on PET-Enhanced Asphalt Mixtures in Hot-Climate Conditions
Received: 3 May 2025 | Revised: 17 May 2025 | Accepted: 31 May 2025 | Online: 2 August 2025
Corresponding author: Anwer M. Ali
Abstract
Asphalt pavements in Iraq face intense summer heat, often exceeding 50 °C, accelerating the binder aging and reducing the pavement life. This study investigates how recycled Polyethylene Terephthalate (PET), added via the dry process, affects the asphalt performance—and how the curing time and temperature influence that effect. A total of 195 Marshall specimens were prepared using five PET dosages (0, 1, 5, 10, and 20% by bitumen weight), cured at two temperatures (50 °C and 70 °C) over three periods (7, 14, and 30 days), plus a control mix with no curing. The results show that 5% PET consistently delivered the best performance. At 70 °C after 14 days, the Marshall stability increased from 14.04 kN to 17.86 kN (27%), and the Marshall Quotient (MQ) rose from 3.41 to 4.28 (over 25%), compared to the control mix, while the flow values remained within the SCRB limits. The statistical analysis confirmed that the PET dosage had the most significant impact (p < 0.0001), accounting for up to 91% of flow variation. The curing temperature affected the flow but not other properties, while the curing time had no significant effect. However, the performance declined sharply with PET contents above 10%. Higher dosages led to reduced density, increased voids, and weaker structural integrity—signaling a clear upper limit for effective PET use. In conclusion, adding 5% PET and curing for at least one week at 50 °C or higher produces a more durable and heat-resistant asphalt mix. The approach not only enhances the mechanical properties, but also offers a sustainable solution by recycling plastic waste into long-lasting pavements. This study investigates the PET modification and controlled curing conditions under extreme climate settings—bridging two underexplored variables in the asphalt performance research.
Keywords:
hot mix asphalt, PET, curing conditions, Marshall properties, volumetric properties, sustainabilityDownloads
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Copyright (c) 2025 Anwer M. Ali, Ahmed D. Abdulateef, Mustafa Q. Khalid, Rasha K. Mahmood, Mustafa M. Ihssan
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