Complex Modulus of Bituminous Mixtures Modified with PVC Waste Using Dynamic Mechanical Analysis

Abstract Asphalt pavements are subject to deterioration due to climatic and mechanical effects, which progressively impair the physical and chemical properties of asphalt mixtures and reduce their durability. At the same time, plastic waste, particularly polyvinyl chloride (PVC), represents a major environmental concern by polluting ecosystems, depleting resources, and contributing to climate change. In this study, PVC waste was incorporated into hot mix asphalt (HMA) to improve mechanical performance while reducing environmental impact. The complex modulus (E*) and related parameters (E′, E″, and phase angle δ) were evaluated using dynamic mechanical analysis (DMA) at temperatures ranging from 10.5 to 25.5°C and loading frequencies between 0.5 and 20 Hz. The results indicate that E* decreases with increasing temperature, accompanied by a higher phase angle, reflecting a loss in stiffness. However, the PVC-modified mixture exhibited improved stiffness and resistance to deformation compared to the control mixture, with an average improvement of 8%. The results showed that modified HMA-PVC improved stiffness, with an average increase of 8%. To further analyze the viscoelastic response, the Williams-Landel-Ferry (WLF) model was applied to shift modulus-frequency curves and construct a master curve at a reference temperature. The WLF-based master curve confirmed that the PVC-modified mixture achieved enhanced stiffness and improved resistance to permanent deformation, supporting greater durability under varying climatic and loading conditions. In addition to mechanical benefits, the use of PVC supports environmental sustainability by reducing plastic waste.