Rheological, chemical and short-term aging properties of waste polyurethane particles modified asphalt binder with or without SBS

In order to effectively dispose of waste polyurethane (WPU) and obtain modified asphalt binders with excellent properties, WPU particles are used to modify asphalt binder. Conventional properties and thermal storage stability of asphalt binders are analyzed, their rheological properties and creep recovery properties are tested by the dynamic shear rheological (DSR). Microstructure, molecular weight and chemical structure of the asphalt binders are analyzed by fluorescence microscopy (FM), gel permeation chromatography (GPC) and fourier transform infrared spectroscopy (FTIR) respectively. Results show that low temperature crack resistance of base asphalt binder is improved due to WPU particles addition, which impairs the property of SBS modified asphalt binder. After short-term aging, the Jnr at 3.2 kPa (Jnr3.2) of modified asphalt binder with WPU particles is less than 2.0 kPa-1. And Jnr3.2 of base asphalt binder decreases by 52.4 % due to WPU particles addition, it is 25.5 % for SBS modified asphalt binder. The thermal storage stability of WPU particles modified asphalt binder is poor and improved by 42.3 % due to the SBS use. The rod-shaped WPU particles are found in modified asphalt binder without SBS, and their structure is destroyed during aging, forming numerous small particles and small molecular products, which improve rutting resistance of asphalt binder. When aged at 150 C, 163 C and 180 C, addition of WPU particles makes aging resistance of base asphalt binder increase by 0.9 %, 1.5 % and 1.2 % respectively, which impairs the aging resistance of SBS modified asphalt binder by 0.9 %, 5 % and 5.3 % respectively. FTIR results manifest decomposition reaction presented in WPU during preparation and aging, forming products with C--O.

Automated summary

The waste polyurethane (WPU) particles are used to modify asphalt binder in order to obtain modified asphalt binders with excellent properties. The addition of WPU particles improves the low temperature crack resistance of the base asphalt binder but impairs the property of SBS modified asphalt binder. The thermal storage stability of the WPU particles modified asphalt binder is poor but can be improved by using SBS. The rod-shaped WPU particles enhance the rutting resistance of the asphalt binder, however, their structure is destroyed during aging process.