Optimization of Semidense Bituminous Concrete Mix Gradation for Foam-Mix Asphalt Containing Agricultural and Industrial Wastes

In recent times, reclaimed asphalt pavement (RAP) has gained popularity among researchers for its low-impact development abilities and socioeconomic factors. But its application in modern construction is still restricted to 10%-30% due to the heterogeneous behavior of the resulting mixtures. The current study investigated the possibilities of increasing RAP integration for foam-mix asphalt synthesis with alternative mineral fillers derived from industrial and agricultural waste-namely, fly ash and sugarcane ash, respectively. To assess the influence of RAP and other fillers on the structural and functional parameters of foam-mix asphalt such as indirect tensile strength, resilient modulus, rutting resistance, abrasion resistance, and Marshall stability were measured. The study indicated that the addition of sugarcane ash and fly ash improves the indirect tensile strength of the foam mixtures. Furthermore, fly ash has better performance than sugarcane ash in terms of tensile strength; however, the reverse trend was found for abrasion and rutting resistance. Lastly, CO2 emissions for the designed mixtures were evaluated using emission factors, which showed that the lower-temperature mixes have lower emission rates than higher-temperature mixes, primarily due to the energy involved in heating bitumen for foam-asphalt mixtures. (c) 2023 American Society of Civil Engineers.