Mechanical properties and environmental sustainability of loess reinforced with recycled zongzi-leaf fibers

Loess is characterized by high porosity, loose structure, and poor water stability, which pose significant challenges to geotechnical engineering. In this study, the recycled zongzi-leaf fibers were innovatively used to reinforce the loess. First, we investigated the surface characteristics and tensile strength of the zongzi-leaf fibers. Then, we explored the effects of fiber type (natural, recycled), fiber length (10 mm, 15 mm, 20 mm), and fiber content (0 %, 0.1 %, 0.2 %, 0.3 %, 0.4 %) on the mechanical properties, reinforcement mechanisms, and microstructure of loess using unconfined compressive strength (UCS) tests, triaxial shear tests, and scanning electron microscope (SEM). Additionally, the environmental impacts of using zongzi-leaf fibers to reinforce loess were evaluated through life cycle assessment (LCA). The results showed that the recycled fibers had reduced roughness, increased contact angle, decreased surface energy, and lower overall tensile strength compared to the natural fibers. The UCS, shear strength, and ductility of the zongzi-leaf fiber-reinforced loess were effectively improved compared to those of the control group. The optimal fiber length and content were 15 mm and 0.3 %, respectively. Below this content, the reinforcement was insufficient, whereas above it, fiber agglomeration decreased the strength of the sample. SEM images revealed that the primary reason for the improved strength was the interfacial bonding between the fibers and soil matrix, along with the constraining behavior of the spatial structure of the fibers. LCA results indicated that zongzi-leaf fibers have a significant environmental advantage over traditional reinforcement materials. These findings provide valuable guidance for the promotion and application of zongzi leaves in geotechnical engineering. • Innovative use of recycled zongzi-leaf fibers to reinforce loess. • Effective improvement of mechanical properties of loess by zongzi-leaf fibers. • The reinforcement mechanism is analyzed by combining macro and micro methods. • Significant environmental benefits of using zongzi-leaf fibers for loess reinforcement.