Abstract
To expand the application range of modified asphalt and mixtures and effectively reduce the aggregation of nanomaterials in asphalt, nanocarbon/styrene butadiene styrene (SBS)/rubber powder composite-modified asphalt is proposed. This paper presents a laboratory study on the performance of nanocarbon/copolymer SBS/rubber powder composite-modified asphalt, and nanocarbon particles modified by titanate coupling agents as modifiers are selected. The nanocarbon/copolymer SBS/rubber powder composite-modified asphalt was prepared by a high-speed shearing method. The physical properties and rheological performance were assessed using ductility tests, softening point tests, penetration tests, dynamic shear rheometer (DSR) tests, and bending beam rheometer (BBR) tests. Furthermore, the mixture properties, including the high-temperature stability, low-temperature cracking resistance, moisture stability, and freeze-thaw splitting, were evaluated in the laboratory. The micromorphology of the base asphalt and composite-modified asphalt was examined by scanning electron microscopy (SEM), and the reactions between the modifiers and AH-70 base asphalt were studied by Fourier transform infrared spectroscopy (FTIR). The results reveal that the surface-modified nanocarbon and rubber powder additives substantially increased the softening point and penetration index of the base asphalt, with little obvious influence on the low-temperature performance. In addition, when nanocarbon/copolymer SBS/rubber powder composite-modified asphalt was used, the high-temperature stability and low-temperature cracking resistance of the nanocarbon/copolymer SBS/rubber powder composite-modified asphalt mixture were approximately 1.3 times those of the nanocarbon/rubber powder asphalt mixture. In terms of the micromorphology and reaction, the addition of the nanocarbon can increase the compatibility between the base asphalt and rubber powder, and then the addition of copolymer SBS can improve the structure of nanocarbon (after surface modification)/rubber powder-modified asphalt to form a stable network. Moreover, the physical reaction plays the dominant role in the modification process for the rubber powder and base asphalt, and chemical reactions occur in the modification process for the surface-modified nanocarbon and base asphalt.
Highlights
In road engineering, asphalt pavement is widely used due to its smooth surface, comfortable driving, low vibration, low noise, and short construction period
He and authors conducted research on SBS/rubber powder-modified asphalt, and the results showed that the flexibility and structure of the SBS/rubber powder composite-modified asphalt after UV aging were not greatly affected
The carbon nanoparticles and the base asphalt were sheared together in a high shear emulsifier for 20 min with a rotation speed of 1500 r/min at 160°C. en, the mixture was stirred with a shear rotation speed of 4000 r/min for 30 min at 160°C by a high shear emulsifier to obtain the nanocarbon-modified asphalt. e copolymer SBS was added into the nanocarbon-modified asphalt at 180°C for 20 min with a shear rotation speed of 1500 r/min by stirring, and the mixture was stirred with a shear rotation speed of 5000 r/min for 40 min at 180°C by a high shear emulsifier. ird, the rubber powder and nanocarbon/SBS-modified asphalt were sheared together for 20 min with a rotation speed of 1500 r/min at 180°C by stirring
Summary
Asphalt pavement is widely used due to its smooth surface, comfortable driving, low vibration, low noise, and short construction period. Sun and authors reported that a compositemodified technique using nano-SiO2, styrene butadiene rubber (SBR) and polyethylene (PE) could comprehensively improve the high-temperature performance, low-temperature performance, and aging resistance of asphalt binders [12] He and authors conducted research on SBS/rubber powder-modified asphalt, and the results showed that the flexibility and structure of the SBS/rubber powder composite-modified asphalt after UV aging were not greatly affected. Mo and authors performed DSR tests, rutting tests and three-point bending tests and demonstrated that SBS/rubber powder compositemodified asphalt had good performance in both high- and low-temperature environments, and the addition of composite-modified materials improved the rutting resistance and low-temperature crack resistance of asphalt mixtures [14]. From the perspective of environmental protection and modification effects, the use of multiple modifiers to modify asphalt is one of the topics worthy of in-depth study. erefore, based on the comprehensive consideration of environmental protection and modification effects, combined with the research results of our research group [18], this research chose AH-70 base asphalt as the modified object and adopted high-speed shear technology to prepare 2% nanocarbon-modified asphalt, 18% rubber powder-modified asphalt, 2% nanocarbon/18% rubber powder-modified asphalt, and 2% nanocarbon/1.0% copolymer SBS/18% rubber powdermodified asphalt, while the comprehensive performance of the modified asphalt and mixture was evaluated through laboratory tests
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