Influence of multi-dimensional nanomaterials composite form on thermal and ultraviolet oxidation aging resistances of SBS modified asphalt

Abstract

In this study, for enhancing the resistance of asphalt against thermal oxidative and ultraviolet oxidative reaction simultaneously, the concept of multi-dimensional nanomaterials (MDNs) is proposed, referring to combinations of zero dimensional nanomaterials (like nano silica (nano-SiO2), nano zinc oxide (nano-ZnO), or nano titanium dioxide (nano-TiO2)) and two dimensional nanomaterials (like organic expanded vermiculite (OEVMT) or organic montmorillonite (OMMT)). Different combinations of nanoparticles and layered silicates were introduced into styrene–butadiene–styrene copolymer modified asphalt (SBSMA) to obtain the composite of MDNs and SBSMA. The SBSMA binders modified by MDNs were aged by laboratory simulated accelerated aging methods, and the influences of different MDNs composites on the physical and rheological properties of the SBSMA before and after aging were studied. The results show that the low-temperature ductility and the high-temperature performance of SBSMA are enhanced by adding MDNs. Especially, OEVMT + TiO2 and OMMT + TiO2 not only bring about 11.2% increase in ductility but also make SBSMA display the best rutting resistance, and OEVMT + ZnO brings about 23.7% increase in high-temperature viscosity. Furthermore, MDNs can change the trend of viscoelastic behavior of SBSMA with temperature and enhance the elastic response of SBSMA by hindering viscous movements of asphalt molecules. MDNs can effectively alleviate the aging negative effects on physical and rheological properties of SBSMA by hindering the growth of oxidation products and protecting SBS modifier from degradation. Meanwhile, this study indicates that among various MDNs composite forms, OEVMT + TiO2 or OMMT + TiO2 have the most obvious improving effects on both the thermal oxidative and ultraviolet oxidative aging resistances of SBSMA.