Study On The Performance And Characteristics Of Basalt Fiber Reinforced High-viscosity Asphalt And Mixture

Studies on asphalt mixture with excellent pavement performance are important in solving early problems and in extending the service life of the asphalt pavement. This is especially important in long uphill sections in mountainous areas, in regions with high rainfall, in the deck pavement of large bridges, and in special sections with high volumes of traffic. On the basis of recent studies on basalt fiber reinforced asphalt mixture and high-viscosity modified asphalt, this study investigates asphalt performance by using a mixture of basalt fiber and a direct-feeding high-viscosity asphalt modifier. The reinforcing mechanisms were analyzed in order to obtain a high-performance mixture of basalt fiber reinforced high-viscosity asphalt. By using a dynamic shear rheology (DSR) temperature scanning test, a force ductility test and a rotational viscosity test the influence of basalt fiber and a high-viscosity modifier on the viscoelastic characteristics of asphalt were analyzed. Results showed that these two materials significantly changed the viscoelastic characteristics, improved the high-temperature and low-temperature performances and the temperature susceptibility of the asphalt. The improvement mechanism of the high-viscosity modifier on the high-temperature performance of the asphalt was analyzed through differential scanning calorimetry (DSC) and a four-component test. Results showed that the quantity of resin and asphaltene that were stable under high temperatures increased while the aromatic and saturate components that were easy to phase transition decreased. It was also found that the colloidal structure of the asphalt also changed into a gel-type structure. The pavement performance of the basalt fiber reinforced high-viscosity asphalt mixture was evaluated by using the wheel tracking test, the bending-breaking test and the freeze-thawing split test under different temperatures. Results showed that the basalt fiber reinforced high-viscosity asphalt had a better high-temperature stability and water stability. Its relevant indicators were better than those of basalt fiber reinforced SBS-modified asphalt mixture under the same grade, while its low-temperature deformability was not as good. The mixture samples after the freeze-thawing split test were observed under an environmental scanning electron microscope (ESEM), and the acting mechanism of basalt fiber in the asphalt mixture was analyzed. Results indicated that the basalt fiber presented a criss-cross network distribution in the asphalt mixture which was favorable to enhance the strength, elasticity and viscosity. This also constrained or postponed the propagation of micro-fractures.The tensile failure of basalt fiber occurred in the asphalt mixture, suggesting the basalt fiber acted as the reinforcement component. Finally, by using an on-site paving experimental section, the construction process for the mixture of the basalt fiber reinforced high-viscosity asphalt was studied. The blending process of "direct-feeding addition, double dry mixing" was determined and the key indicators for paving and compacting processes are proposed.