Asphalt pavements are a common choice for road construction an‎d repair but deteriorate over time due to factors like heavy traffic an‎d harsh weather, losing their original quality. This process diminishes asphalt pavement efficiency an‎d durability, raising maintenance an‎d repair frequency, while increasing bitumen hardness an‎d reducing its flexibility, further decreasing pavement longevity. Recycling aged asphalts an‎d using rejuvenators is one of the most important issues for reducing costs, conserving resources, an‎d reducing environmental impact. In this study, waste cold rolling oil (WSO) from the Mobarakeh Steel Complex in Isfahan was used as a cheap an‎d available rejuvenator to improve the properties of aged asphalt. To conduct this research, various samples of bitumen including virgin bitumen, aged bitumen called 30P, as well as rejuvenated bitumens by adding specific amounts of WSO at 5 an‎d 10% by weight of virgin bitumen, were prepared based on the Australian Asphalt Pavement Association Mixing Plan method. After preparing the samples, various tests were conducted to thoroughly examine their performance, physical, an‎d chemical properties. These tests include the penetration test to determine the degree of bitumen penetration, the softening point test to determine the softening temperature of bitumen, the rotational viscometer (RV) test, which is used to measure the viscosity of bitumen under various conditions, the dynamic shear rheometer (DSR) to examine the dynamic shear behavior of bitumen, an‎d the bending beam rheometer (BBR) to analyze mechanical properties at low temperatures. Fourier transform infrared spectroscopy (FTIR) was also performed to analyze the chemical structure of the samples an‎d identify possible changes in their chemical composition. This set of experiments provided comprehensive data for a better understan‎ding of the behavior an‎d properties of the bitumen samples. The results showed that mixing virgin bitumen with aged bitumen increased the hardness an‎d reduced the flexibility of virgin bitumen, while adding WSO significantly compensated for these effects. The use of 5 an‎d 10% WSO resulted in a 71 an‎d 108% recovery of the penetration degree, a 44 an‎d 78% reduction in the softening point, improved viscosity, an‎d restored the balance between hardness an‎d flexibility, respectively. Also, DSR an‎d BBR results indicated improved resistance to rutting, fatigue, an‎d thermal cracking in samples containing WSO. Overall, the findings indicate that cold rolling oil waste can be used as an effective rejuvenator to improve the properties of aged bitumen an‎d increase the service life of asphalt pavements. Finally, considering the purpose of this research an‎d most of the physical an‎d performance results, bitumen containing 10% rejuvenator an‎d 30% aged bitumen is introduced as the optimal bitumen.

مهدي ابطحي فروشاني , مهدي حجازي

مهدي ذاكرزاده

محمدعلي روشن ضمير , احمدرضا طالبيان