Study on the Cohesive Characteristic of Nano-SiO2 Bioinspired Grafting Basalt Fiber and Asphalt

To enhance the effective cohesion between basalt fiber (BF) and asphalt, an optimal preparation process of nano-SiO2 bioinspired grafting BF was proposed using a chemical grafting method based on the bioinspired idea of mussel-plaque. The mechanism of nano-SiO2 bioinspired grafted BF was analyzed through micro-morphology, functional group changes, and elemental composition tests. The cohesive characteristics of nano-SiO2 bioinspired grafting BF with asphalt were investigated using direct tension tests and surface energy theory. The results showed that after BF soaking in 3 mol/L HCl solution (BFHCl), nano-SiO2 grafting BF (SiO2-BFHCl) has good wettability with asphalt. Alkali metal ions on the surface of BFHCl were ion exchanged with H+ in the HCl solution, forming new Si-OH bonds and grafting more SiO2. Compared with the original BF reinforced asphalt, the maximum tensile force and ductility of nano-SiO2 grafting BF reinforced asphalt both increased, and the wetting angle with asphalt droplets was SiO2-BFHCl > SiO2-BFNaOH > SiO2-BF > original BF. Based on the surface energy theory, the cohesion functions of SiO2-BF, SiO2-BFNaOH, and SiO2-BFHCl with asphalt were improved by 2.8%, 7.4%, and 11.6%, respectively, compared to that of the original BF.