The synergistic effect of organic montmorillonite and thermoplastic polyurethane on properties of asphalt binder

Abstract This paper aims at investigating the synergistic effect of organic montmorillonite (OMMT) and thermoplastic polyurethane (TPU) on physical and rheological properties of asphalt binder. Herein, the structure and content of OMMT and TPU in asphalt binder were first determined. OMMT/TPU modified asphalt binders were then evaluated by XRD (X-ray diffraction), FTIR (Fourier transform infrared), penetration, softening point, ductility, viscosity, storage stability, DSR (dynamic shear rheometer), BBR (bending beam rheometer) and LOI (limiting oxygen index) tests. Results show that, the increase of OMMT content facilitates storage stability of OMMT/TPU modified binder. Existence of OMMT and TPU with appropriate contents is able to enhance high and low temperature properties, elastic behavior and flame retardancy of asphalt binder. TPU content is the dominant factor of low temperature property, while OMMT content plays a key role in flame retardancy of OMMT/TPU modified binder. Additionally, it is recommended to use 2% OMMT and 9% TPU in asphalt binder. All in all, OMMT and TPU present a good synergy in asphalt matrix.