Effect of the fiber surface treatment on the mechanical performance of bamboo fiber modified asphalt binder

• The properties of silane-treated bamboo asphalt, alkali-treated bamboo asphalt, and heat-treated bamboo asphalt were evaluated and compared. • Silane-treated bamboo fibers exhibit the best interfacial properties with asphalt. • The rheological properties of treated fiber asphalt are improved compared to untreated fiber asphalt. • Silane-treated fiber asphalt has the longest fatigue life of the three treated fiber asphalts. Bamboo fibers exhibit better interfacial properties with asphalt after surface treatment. Therefore, it is essential to evaluate the effect of bamboo fiber surface treatment on asphalt properties. In this paper, the adhesion of bamboo fibers to asphalt after silane coupling agent, alkali treatment, and heat treatment was investigated. And the rheological properties and fatigue performance of the fiber asphalt binder were evaluated. The adhesion and stripping work of the fibers and asphalt were characterized by measuring the contact angle. The microstructure of treated fibers was analyzed using a scanning electron microscope (SEM). The thermal stability of the fibers was then evaluated by thermogravimetric analysis (TG). Finally, the rheological properties and fatigue performance of fiber asphalt were studied by Dynamic Shear Rheological test (DSR), Multiple Stress Creep Recovery Test (MSCR), and Linear Amplitude Sweep tests (LAS). In the SEM images, it can be observed that the silane-treated fibers have a rough surface and multiple independently existing fibers, which can provide support for the fact that the silane-treated fiber asphalt has favorable adhesion. In addition, the silane-treated fibers showed the most significant improvements in wettability and rheology. The adhesion work of silane-treated fibers was 66.7% greater than that of untreated fibers. All treated fiber asphalt showed better rheological properties than untreated fiber asphalt. The addition of treated fibers resulted in lower δ values, higher G*/sin δ, and increased fatigue life of the asphalt. Silane-treated fiber asphalt has the largest G*/sin δ and fatigue life of tested asphalt. Based on the results, several fiber treatment methods are evaluated, improving the reference for choosing a suitable fiber surface treatment for bamboo asphalt.