The use of recycled waste elastic materials provides a cost-effective and environmentally friendly option for further modifying the performance of asphalt mixtures. Therefore, the effects of different proportions of (PMMA) polymethyl methacrylate derived from waste plastic material were evaluated using the Indirect Tensile Strength Test (ITST) of lab-prepared specimens. Since numerous methods of modifying the conventional asphalt binder are available, in this research, the virgin binder was modified with 1%, 2%, 3%, 4% and 5% PMMA for evaluating optimum performance proportions in terms of Marshall stability and ITST of asphalt mixtures. Furthermore, stiffness modulus tests were performed at frequency values of 1.2 Hz, 1.9 Hz, 3.9 Hz and 5 Hz. The effect of the loading rate from 10 MPa/s to 70 MPa/s was evaluated with an increment of 10 MPa/s for all proportions. Moreover, finite element modeling was performed using the data obtained from dynamic modulus tests with modified Burger's Logit model for evaluation of rutting progression. Results show improved performance of asphalt mixtures with the addition of PMMA, leading to variation in properties including penetration, softening point, Marshall stability and rutting resistance. It is recommended to use 5% PMMA for increased indirect tensile strength, Marshall stability, rutting and fatigue damage resistance.

In today's world, construction and infrastructure projects necessitate innovative solutions in environmental sustainability and materials engineering. In this context, research efforts to improve the properties of asphalt mixtures, reduce environmental impacts, and contribute to recycling hold great significance. This study focuses on modifying stone mastic asphalt mixtures with waste material derived from Polymethyl Methacrylate. Using Polymethyl Methacrylate as waste plastic material represents a significant step forward in recycling and sustainable material usage. In the study, Marshall specimens were obtained using Polymethyl Methacrylate in different proportions in bitumen and aggregate. The results of the Marshall specimens were evaluated to determine the usability and optimum ratios of Polymethyl Methacrylate. This study aims to evaluate the impact of Polymethyl Methacrylate on stone mastic asphalt mixtures as a support layer in railway tracks to help reduce noise and vibration. The results demonstrate that varying concentrations of Polymethyl Methacrylate in both aggregate and bitumen significantly alter the mechanical and thermal properties of the asphalt. For instance, incorporating 2.5% Polymethyl Methacrylate in the aggregate increased the VMA to 21, resulting in VFA values of 66. Furthermore, using Polymethyl Methacrylate in the aggregate increased the asphalt samples’ height, ranging from 69 to 72 mm. These findings underscore the effectiveness and feasibility of Polymethyl Methacrylate in sustainable asphalt projects. Following highway technical specifications, incorporating Polymethyl Methacrylate in specific proportions in stone mastic asphalt mixtures can enhance their performance, representing a significant step towards sustainable road construction. However, when the concentration of Polymethyl Methacrylate in the bitumen increased, the bitumen formed deteriorated. Therefore, using waste Polymethyl Methacrylate between 4% and 5% can be considered suitable for improving the properties of bitumen against sustainability and temperature concerns.