Mechanical properties, microstructural evolution, and environmental impacts of recycled polypropylene fiber stabilized loess

The deterioration of polypropylene fiber (PF) stabilized loess and its environmental performance are crucial factors for assessing the effectiveness of its reinforcement against frequent collapse and spalling induced by drying and wetting (D-W) cycles. For this purpose, the influence and underlying mechanisms of recycled PF content (0%, 0.1%, 0.3%, 0.5%, and 0.7%) and the number of D-W cycles on the strength, ductility, and resistance to deterioration of PF stabilized loess were investigated. Additionally, a life cycle assessment (LCA) was conducted to analyze the environmental impact of PF production. The results demonstrate a significant improvement in the strength, ductility, and resistance to deterioration of the samples upon the addition of PF. Although the initial five D-W cycles led to a decrease in specimen strength, they concurrently enhanced the ductility. Optimal mechanical properties were observed at fiber content of 0.5%, resulting in a remarkable in-crease in strength by 123.26% and resistance to deterioration by 25.49%. Specimens with 0.5% fiber content exhibited a three-dimensional network structure, contributing to enhanced mechanical properties compared to specimens with lower and higher fiber contents that exhibited dispersed and planar agglomerated structures. The study advocates for the use of industrial recycled PF in loess reinforcement, which exhibits significant advantages in terms of greenhouse gas emissions and energy demand when compared to virgin PF and domestic recycled PF. This innovative investigation provides insights into the durability and environmental impact of PF-stabilized loess and establishes a theoretical foundation for promoting the widespread utilization of PF in the loess foun-dation reinforcement market.