Properties deterioration of recovered bitumen under coupling multi-environment factors based on the ageing simulation device

The properties of pavement bitumen deteriorates when exposed to complicated environmental factors. This study developed a multi-environment simulation device to apply multi-factor coupling on asphalt mixtures. The physicochemical properties of recovered bitumen were analysed by traditional technical indicators, tensile strength, fourier transform infrared spectroscopy, and contact angle tests. The ageing index and target functional group index ratio were proposed to quantify the interactions of environmental factors. The results indicated that surface morphology of mixtures was severely affected by multi-factor coupling. The multi-factor coupling exacerbated the deterioration of physical properties and increased tensile strength, surface free energy, and adhesion work. However, the sulfoxide index was more affected by thermal ageing than the carbonyl index, and its change under ultraviolet and multi-factor actions was not obvious. The ageing index and target functional group index ratio indicated that the effect of ultraviolet-thermal coupling had the largest effect on the physicochemical properties of bitumen.