In the recent times, asphalt binder modification has emerged an inevitable alternative in the paving industry to ensure better performing pavements against the distresses caused by common factors such as; moisture susceptibility and high-temperature sensitivity of asphalt binders. Nanomaterials, as asphalt-modifiers, have proved to be the most promising materials in the industry owing to their higher active surface area and small particle size. This study was devoted to assessing the modification influence of three different types of nanomaterials, including nano-Bentonite, nano-CaCO3, and ZycoTherm, on the properties of asphalt binder and HMA. Conventional and rheological tests on asphalt binders, as well as, Marshall mix design and modified Lottman test on laboratory-prepared HMA specimens were conducted in order to signify the influence of nanomodification. The research findings suggested that nanomaterials can potentially enhance the high-temperature susceptibility resistance, storage stability, and rheological properties of asphalt binder samples. Mix design results revealed that the optimum binder contents decreased and Marshall stabilities were slightly improved with nanomodification. Moreover, the modified Lottman test results indicated that 0.1 % of ZycoTherm increased the TSR by 22 % as compared to the control mixture that infers its efficiency in terms of improving the HMA resistance against the moisture-induced damages.

Asphalt pavements are amongst the most recycled materials in the contemporary world depending on the environmental and financial advantages. The introduction of Recycled Asphalt Pavement (RAP) on newly produced asphalt pavement is possible by the utilization of rejuvenating agents, which should contain oily fractions. For this purpose, within the scope of this study, three types of agents with optimum amounts (by weight of bitumen) were utilized 5.4% Waste Engine Oil (WEO), 5.1% Waste Vegetable Oil (WVO), and 6.8% Commercial Rejuvenating Agent (CRA). The highest applicable RAP content in mixtures depends on the rejuvenator type determined by Marshall Mix Design tests (air voids, flow, and stability). Rejuvenation facilitated the use of 50 to 60% of additional RAP material in the mixtures depending on the rejuvenator type. Indirect Tensile Strength (ITS) test results declared that RAP mixtures, when subjected to the rejuvenation process, resulted in relatively less brittleness and enhanced durability properties compared to the unmodified ones. Additionally, cost comparison analyses demonstrated encouraging results as the cost-benefit ratio exceeded up to 55% for mixtures involving high percentages of rejuvenated RAP. As a final analysis, Return on Investment (ROI) values were calculated for each rejuvenator type by the cost of upgrading the facility to handle RAP and the profit of RAP usage. Consequently, ROI was calculated as a return time in months, which unveils an extremely profitable opportunity in the industry.

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