Thermoplastic Polyurethane/Bitumen Blends as Smart Materials: Integrating Shape Memory and Self‐Healing Properties for Sustainable Applications

ABSTRACT This study pioneers a novel strategy for creating smart polymer composites by incorporating thermoplastic polyurethane (TPU) into a bitumen matrix, successfully integrating dual shape memory and autonomous self‐healing functionalities. Comprehensive characterization confirms excellent polymer‐matrix compatibility, with FT‐IR spectroscopy revealing chemical interactions at the interface. The modification drastically improved the composite's performance: the softening point increased from 46.7°C to 60.2°C, and the tensile strength surged by over 120% at 20°C for the 8.0 wt.% blend. Rheological tests showed enhanced viscoelastic properties and resistance to high‐temperature deformation. Remarkably, the composite achieved up to 81% shape recovery and a self‐healing efficiency of 85%, quantitatively assessed via a beam on elastic foundation (BOEF) method. We elucidate a synergistic multi‐scale healing mechanism where thermal stimulation triggers the TPU's shape memory effect to close cracks, thereby creating a conducive interface for intensive molecular diffusion and entanglement. This work validates a groundbreaking and generalizable polymer‐based paradigm for developing next‐generation smart composites with enhanced durability and multi‐functionality for sustainable pavement applications.