Research on the Properties of Low Temperature and Anti‐UV of Asphalt with Nano‐ZnO/Nano‐TiO₂/Copolymer SBS Composite Modified in High‐Altitude Areas

Abstract

Strong ultraviolet light and low-temperature are the typical environmental characteristics in high-altitude areas. The performance of SBS-modified asphalt in the above environmental characteristics needs further study. To improve the resistance ultraviolet (UV) ageing and low-temperature performance of copolymer- (SBS-) modified asphalt, an SBS-modified asphalt containing nano-ZnO and nano-TiO2 is proposed. In this paper, nano-ZnO, nano-TiO2, and SBS were used as modifiers with the silane coupling agent (KH-560) as the nanomaterial surface modification. The orthogonal test table was used to analyse the effects of the three modifiers on the physical properties of modified asphalt at different dosages. On this basis, the physical properties, low-temperature properties, and ageing indices (carbonyl index and sulfoxide index) were studied for base asphalt, SBS-modified asphalt, nano-ZnO/SBS-modified asphalt, and nano-ZnO/nano-TiO2/SBS composite-modified asphalt before and after photoaging. The content changes of characteristic elements (Zn and Ti) in the nano-ZnO/nano-TiO2/SBS composite-modified asphalt before and after ageing were studied by scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS), and the UV ageing mechanism was revealed. The results indicate that two nanoparticles show the best compatibility with asphalt after surface modification and can improve the binding ability between SBS and base asphalt. The orthogonal test analysis shows that nano-ZnO has a highly significant effect on the low- and high-temperature performance of the nano-ZnO/nano-TiO2/SBS composite-modified asphalt, and nano-TiO2 has a significant effect on the high-temperature performance. Three optimal composite-modified systems for base asphalt including 4% nano-ZnO/1.5% nano-TiO2/3.2% SBS were proposed and had the best antiaging ability. Compared with the sulfoxide index, the carbonyl index changed most obviously before and after ageing. Additionally, the results reveal that nano-TiO2 has a good absorption effect at a wavelength of 365 nm (ultraviolet light), while nano-ZnO is liable to photolysis, and its activity decreases at this wavelength.

Investigating the pavement performance and aging resistance of modified bio-asphalt with nano-particles

“…The mechanism of asphalt aging comprises the volatilization and transformation of the dispersed phase under the action of high temperatures and ultraviolet irradiation [ 34 , 35 ]. As previously mentioned, the proportion of the dispersed phase decreases with the addition of the nano-particles; thus the aging resistance of the nano-modified bio-asphalt binder is improved.…”

“…An asphalt binder can be treated as a mix of three types of distributed systems: a matrix phase, dispersed phase, and bee-like structure. The softening point of the asphalt binder increases as the proportion of the matrix phase increases, and the 5˚C ductility and 25˚C penetration increase as the proportion of the dispersed phase increase [30][31][32][33][34][35]. Evidently, the proportion of the dispersed phase in the asphalt binder increases with the addition of bio-oil [30].…”

“…Moreover, on the whole, the loss ratios of the nano-modified bio-asphalt binders using nano-SiO 2 are the lowest and those using nano-CaCO 3 are the highest, showing the same law as the mass loss and the residual penetration ratio. The mechanism of asphalt aging comprises the volatilization and transformation of the dispersed phase under the action of high temperatures and ultraviolet irradiation [34,35]. As previously mentioned, the proportion of the dispersed phase decreases with the addition of the nano-particles; thus the aging resistance of the nano-modified bio-asphalt binder is improved.…”

Research on the Influence of Nanocarbon/Copolymer SBS/Rubber Powder Composite Modification on the Properties of Asphalt and Mixtures

“…is is because the modified nanocarbon and asphalt macromolecule chemical bonds are generated by the rupture of unsaturated bonds, and free radical groups undergo a chemical reaction, indicating that after surface modification by the coupling agent, both a chemical reaction and a physical reaction occur between the nanocarbon and the base asphalt. Figure 16 shows that the combined use of several modifiers does not produce a new absorption peak, except for the characteristic peak of copolymer SBS at 699 cm −1 and butadiene at 966 cm −1 , which is only a difference in transmission [33]. e slight changes in the other peak wave positions are caused by free radicals generated by the breakage of a small amount of polymer macromolecules during the highspeed shearing of rubber powder and SBS particles.…”

Ultraviolet aging study on bitumen modified by a composite of clay and fumed silica nanoparticles

“…However, there are few works related to the effect of NPs on ultraviolet aging properties of bitumen. Titanium dioxide, cuprous oxide, zinc oxide, silicon dioxide, and montmorillonite are some NPs that have been used for improving bitumen aging resistance to UV radiation [13][14][15][16][17] .…”