Physical and Rheological Properties of Asphalt Binder Modified with Recycled Fibers

The price of asphalt binder has increased dramatically due to the increase in oil prices and the increase in traffic volumes occurring worldwide. This situation has prompted calls for greater viscosity, lower-cost asphalt for pavement construction, and the development of alternative materials that have a good rheological effect, are less expensive, and have a reduced negative impact on human health and the environment. The application of fibers in asphalt mixes has been studied over the past few decades to improve pavement performance around the world. This study was conducted on three types of asphalt binders that were modified with two types of fibers: brown recycled wool fiber (BRWF), available locally in Iraq, and China polyester fiber (CPF), which is considered as waste, to produce fiber-modified asphalt binders. The samples were conducted using traditional physical testing (penetration, softening point, and rotational viscosity tests) as well as the Dynamic Shear Rheometer (DSR) test. In comparison to the original asphalt binders, the fiber-enhanced asphalt binders had greater softening point, viscosity, and complex modulus but decreased penetration. The tests revealed that using both kinds of fibers as modifiers for asphalt binders improves their high-temperature performance by increasing the grade of the control binders (PG). This increase in asphalt binder stiffness is anticipated to enhance pavement rutting resistance. Consequently, these fibers can be used as additives for asphalt binders and asphalt mixtures to enhance their performance.