Semnan University Press Journal of Transportation Infrastructure Engineering 2423-5350 11 2 2025 06 22 Laboratory Study on the Effect of Rejuvenator (Rapiol) on the Fatigue Life of Unaged and Aged Asphalt Binder and Hot Mix Asphalt Laboratory Study on the Effect of Rejuvenator (Rapiol) on the Fatigue Life of Unaged and Aged Asphalt Binder and Hot Mix Asphalt 85 104 9836 10.22075/jtie.2025.37651.1722 FA Ehsan Mansour Kiaei Department of Road and Transportation Engineering, Faculty of Civil Engineering, Semnan University, Semnan, Iran Mahdi Akbari Faculty of Civil Engineering, Semnan University, Semnan, Iran 0000-0002-9359-5095 Journal Article 2025 05 05 Fatigue cracks are considered as one of the most significant pavement failures. The cause of fatigue cracks is the changes in environmental temperature conditions and repeated loading of vehicles. Additives can enhance the tensile strength of asphalt pavement layers and increase their life. In this article, through laboratory studies, the effect of using a rejuvenator as an additive in asphalt mixture, called “Rapiol”, on improving the fatigue performance of both unaged and aged asphalt pavements was investigated. To achieve this, the study utilized the Linear Amplitude Sweep (LAS) test at strain levels of 2.5% and 5%, and the Four-Point Bending Beam (4-PBB) test in strain-control mode (at strain levels of 400, 600, and 800 microstrains). The LAS test results indicate that in unaged conditions, the Rapiol rejuvenator improved fatigue life by 7.5% and 3% at strain levels of 2.5% and 5%, respectively. However, in aged samples, fatigue life increased by 4.1% at 2.5% strain but decreased by 21.8% at 5% strain. Moreover, according to the 4-PBB test results, using Rapiol in unaged asphalt mixture samples enhanced fatigue life by 42% and 284% at 400 and 800 microstrains, respectively. Similarly, in aged asphalt mixture samples, fatigue life increased by 100% and 500% at 400 and 800 microstrains, respectively. Fatigue cracks are considered as one of the most significant pavement failures. The cause of fatigue cracks is the changes in environmental temperature conditions and repeated loading of vehicles. Additives can enhance the tensile strength of asphalt pavement layers and increase their life. In this article, through laboratory studies, the effect of using a rejuvenator as an additive in asphalt mixture, called “Rapiol”, on improving the fatigue performance of both unaged and aged asphalt pavements was investigated. To achieve this, the study utilized the Linear Amplitude Sweep (LAS) test at strain levels of 2.5% and 5%, and the Four-Point Bending Beam (4-PBB) test in strain-control mode (at strain levels of 400, 600, and 800 microstrains). The LAS test results indicate that in unaged conditions, the Rapiol rejuvenator improved fatigue life by 7.5% and 3% at strain levels of 2.5% and 5%, respectively. However, in aged samples, fatigue life increased by 4.1% at 2.5% strain but decreased by 21.8% at 5% strain. Moreover, according to the 4-PBB test results, using Rapiol in unaged asphalt mixture samples enhanced fatigue life by 42% and 284% at 400 and 800 microstrains, respectively. Similarly, in aged asphalt mixture samples, fatigue life increased by 100% and 500% at 400 and 800 microstrains, respectively. https://jtie.semnan.ac.ir/article_9836_4cef6451a60919d23a334fc56be649e5.pdf