Characterization of binders recovered from RAP and recycling agents as a basis for evaluating the gree of mixing

Given the need to improve the performance of asphalt pavements, the search for techniques that are durable and sustainable has become a reality in the paving industry. This includes the adoption of methodologies and new materials focused on reducing CO₂ emissions, with an emphasis on the use of RAP in recycled asphalt mixtures, specifically in analyzing the properties of the residual binder. In this context, the study evaluated the properties of binders recovered from RAP used in recycled asphalt mixtures. To this end, the binder was characterized with a focus on obtaining parameters that describe the interaction of the oxidized material with the other binders in the mixture. Laboratory analyses and performance tests revealed high stiffness in the recovered binder and in the blends containing higher proportions of that material, resulting in good rutting performance, although the fatigue resistance and integrity of both the isolated material and the binder blends were compromised; this can be explained by differences in viscosity and by the recovery observed when a recycling agent was incorporated. Based on this study, it can be concluded that complete blending of the binders does not depend solely on the characteristics of the blended materials, but also on boundary conditions, such as temperature, mixing time, and conditioning.