Compared with traditional asphalt, emulsified asphalt occurs to be a better low-temperature usability and environmental adaptability, which can reduce environmental pollution and energy consuming during road construction. The low-temperature ductility is a very important indicator to evaluate the environmental adaptability of emulsified asphalt. However, the relevance between microstructure and low-temperature ductility of modified asphalt is still rarely reported. Herein, we reported the first successful unfolding of the microscopic mechanism of ductility attenuation of the modified emulsified asphalt by combining experiments and characterization: Emulsifiers and additives had greater influence on the low-temperature ductility. Anionic and cationic emulsifiers had the similar ductility loss. Adding a non-ionic emulsifier OP-10 could be a solution to improve the ductility. The effect of the temperature change occurred less significant compared to the pH evolution of surfactant solution. The grey relation entropy (GRE) analysis revealed that the emulsifier structure (C/H ratio) would be the most important factor to affect the low-temperature ductility. The macro, micro and nano scales of modified emulsified asphalt were correlated, revealing in-depth that the aggregation and inter-chains interaction of styrene-butadiene-styrene (SBS) were the internal mechanism leading to the ductility loss. The change of glass transition temperature (Tg) was proposed to correlate the microstructural factor with the
ductility. Moreover, the combination of ductility test and bending beam rheometer (BBR) test could be an effective way to evaluate the low-temperature performance of asphalt.@en

This study aims to comprehensively investigate the rejuvenation efficiency of various self-developed compound rejuvenators on the physical, mechanical, and aging properties of aged bitumen, asphalt mortar, and mixture. The results revealed that the restoration capacity of vacuum distilled-oil rejuvenators on high-and-low temperature performance-grade of aged bitumen is more significant. In contrast, an aromatic-oil based rejuvenator is good at enhancing low-temperature grade and aging resistance. Moreover, the temperature and time of the curing conditions for mixing recycling of asphalt mixture were optimized as 150 °C and 120 min. Furthermore, the sufficient anti-rutting, structural stability, and moisture resistance of recycled asphalt mixture affirmed the rejuvenation efficiency of compound rejuvenators. @en

The objective of this study is to estimate the effects of using waste cooking oil (WCO), waste engine oil (WEO) as well as styrene butadiene rubber (SBR) on the performance restoration and improvement for aged asphalt. The rheological properties of aged and rejuvenated asphalts were assessed using rotational viscometer (RV), dynamic shear rheometer (DSR) and bending beam rheometer (BBR) methods. Moreover, compatibility, aging properties and rejuvenation mechanism of rejuvenated asphalts were also explored. The results revealed that WCO and WEO both strengthened the viscous properties, fatigue and cracking resistance, but adversely affects the temperature sensitivity, rutting resistance, elastic recovery, compatibility and aging properties of rejuvenated asphalt. Meanwhile, adding SBR further improved the temperature sensitivity, high and low temperature performance, compatibility as well as aging resistance of rejuvenated asphalt. Besides, WCO rejuvenated asphalt had some advantages in fatigue cracking resistance performance, while WEO rejuvenated asphalt possessed better rutting resistance, creep recovery and compatibility. Furthermore, Fourier transform infrared (FTIR) spectroscopy test showed that the physical blending mainly determined the rejuvenation mechanism when both waste oil and SBR was used in aged asphalt. Considering overall performance of rejuvenated asphalt, the optimum dosage of waste oil and SBR were recommended as 10 wt% and 3 wt%, respectively.

@en

It is well known that crumb rubber (CR) and styrene–butadienestyrene (SBS) composite modified asphalt has better rheological and engineering performance. However, it always presents very poor compatibility and storage stability. Meanwhile, Trans-polyoctenamer (TOR) can effectively improve the compatibility and thermal stability of rubber asphalt. Thus, this study aims to investigate the effectiveness of TOR on rheological properties, microstructure and thermal stability of CR/SBS modified asphalt. The results show that TOR has a significant influence on strengthening anti-rutting and temperature sensitivity of CR/SBS modified asphalt. However, TOR has a slightly negative influence on the anti-cracking ability for CR/SBS modified asphalt, which still maintains the critical low temperature requirement. Furthermore, TOR could be able to promote the conformation of cross-linked structure between polymer and asphalt, resulting in a significant enhancement in rheological properties and thermal stability of CR/SBS modified asphalt. Lastly, the effects of TOR on viscoelastic performance for modified asphalt markedly depend on the component of neat asphalt, and high asphaltene content is beneficial for improving the rheological behavior effects of TOR.@en

Recycling technology is widely used in the asphalt road construction due to its environmental and economic effects. Many efforts have focused on the performance restoration of aged base asphalt by adding light oil, but the possibility of recycling the aged asphalt using low-viscosity asphalt and polymers has been few explored. Therefore, the objective of this research is to use polymer-modified low-viscosity asphalt as rejuvenator to recycle the aged asphalt. The conventional properties, rheological behaviors as well as anti-aging performance of polymer-modified recycled asphalts were evaluated by rotational viscosity (RV) tests, dynamic shear rheometer (DSR) tests and bending beam rheometer (BBR) tests. Moreover, the effects of the concentration ratio between polymer-modified low-viscosity asphalt rejuvenator and aged asphalt on the high-temperature anti-rutting, low-temperature cracking resistance, fatigue and aging resistance abilities of recycled asphalt were studied. The results show that the low-viscosity asphalt can increase viscous components and restore the workability of aged asphalt. However, the addition of low-viscosity asphalt weakens the high-temperature properties, temperature sensitivity and anti-aging performance of aged asphalt. Fortunately, the high-temperature rutting resistance, temperature sensitivity, viscoelastic properties, low-temperature cracking resistance, anti-fatigue and aging resistance performance of recycled asphalt can be enhanced remarkably by adding SBS and CR. Meanwhile, SBS-modified recycled asphalt has better fatigue and low temperature cracking resistance properties, while CR-modified recycled asphalt has the advantages on the rutting resistance, anti-aging and temperature sensitivity performance. Furthermore, SBS5-5 and CR6-4 modified recycled asphalts both have better pavement performance than others, which is superior to the requirements of polymer modified asphalt. Therefore, it is meaningful and feasible to recycle the aged base asphalt to be polymer-modified asphalt.@en

A styrene-butadiene-styrene (SBS) latex modifier can be used for asphalt modification due to the fact of its energy-saving, construction convenience, and economic advantages. The objective of this study was to investigate the influence of asphalt type and SBS latex dosage on the rheological properties, compatibility, and storage stability of asphalt through temperature and frequency sweep, steady-state flow, multiple stress creep and recovery (MSCR) tests, Cole-Cole plots and thermal storage tests. The results indicated that high SBS latex content is beneficial for improving anti-rutting, anti-fatigue, viscous flow resistance, and elastic recovery abilities of modified asphalt. The chemical composition of asphalt had a significant effect on the properties of the SBS latex-modified asphalt. High asphaltenes and low resins were favorable to enhancing anti-rutting and recovery properties but weakened the anti-fatigue, compatibility, and storage stability of modified asphalt. Furthermore, compared to SBS particle-modified asphalt, SBS latex-modified asphalt had greater rutting and fatigue resistance. However, SBS latex-modified asphalt had some disadvantages in compatibility and storage stability. Comprehensively considering the balance of viscoelastic properties, compatibility, and storage stability of SBS latex-modified asphalt, the mixing dosage of SBS latex modifier is recommended at 4.0 wt% which could feasibly replace SBS particle in asphalt modification.

@en