Sustainable Asphalt Concrete Optimization using Natural Aggregates, Reclaimed Asphalt Pavement (RAP), Incinerator Bottom Ash (IBA), and Polymer Binder Substitutes

<p dir="ltr">This research investigates the optimization of sustainable asphalt concrete (SAC) by incorporating Reclaimed Asphalt Pavement (RAP), Incinerator Bottom Ash (IBA), and polyethylene terephthalate (PET) as substitutes for virgin aggregates and bitumen. Previous studies on sustainable asphalt concrete have often focused on specific case studies or limited aspects of material substitution. This research aims to provide a comprehensive evaluation of the performance and environmental benefits of these materials in SAC mixtures.</p><p dir="ltr">To achieve this objective, a series of laboratory experiments were conducted to assess the indirect tensile strength, Marshall stability, and other relevant properties of asphalt concrete mixtures containing varying proportions of RAP, IBA, and PET. The optimal substitution levels for each material were determined through a systematic analysis of the experimental data.</p><p dir="ltr">The findings of this research demonstrate that RAP can be effectively used as an aggregate replacement at a substitution level of 45% by mass. IBA, on the other hand, can be incorporated as an aggregate replacement at a substitution level of 10% by mass. The use of PET as a binder substitute proved to be beneficial, with optimal substitution levels varying depending on the aggregate type. For IBA-based mixtures, a 10% PET replacement was found to be effective, while a 2% PET replacement was suitable for RAP-based mixtures.</p><p dir="ltr">The combined use of RAP, IBA, and PET in asphalt concrete mixtures offers significant potential for reducing the environmental impact of road construction. By substituting virgin materials with recycled components, carbon emissions can be substantially decreased. This research provides valuable insights for policymakers, engineers, and industry professionals seeking to implement more sustainable practices in road construction.</p>