This thesis investigates the mechanical performance of sustainable asphalt mixtures incorporating recycled plastic shreds for different pavement layers. The mixtures considered in this study were developed in previous stages of the Green Roads project; therefore, the present work does not focus on mix design optimization, but rather on the advanced mechanical characterization of the produced mixtures under laboratory-controlled conditions. The experimental program was carried out using the Asphalt Mixture Performance Tester (AMPT) and complementary analytical procedures. The mechanical response of the mixtures was evaluated through dynamic modulus testing, master curve construction, cyclic fatigue characterization, and low-temperature cracking analysis. Both large and small cylindrical specimens were considered, depending on the specific testing procedure and material availability.