Application of plant fibers in subgrade engineering: current situation and challenges

Abstract

The application of plant fibers in subgrade engineering is increasingly receiving attention. As a sustainable material, plant fibers possess characteristics such as lightweight, renewability, and biodegradability. The morphology, chemical composition, mechanical properties and hydraulic properties of plant fibers determine their application scenarios in subgrade engineering. Degradation is also an important factor affecting the long-term performance of plant fibers. In order to overcome their limitations in subgrade engineering, physical and chemical modification has become necessary. Through physical or chemical modification, the compatibility between plant fibers and the matrix can be enhanced, improving dispersibility and adhesiveness. Plant fibers can be applied in subgrade engineering through methods such as soil improvement, incorporation into geosynthetic materials, and the use of prefabricated components. Among these, soil improvement with plant fiber can enhance soil crack resistance and stability, adding fibers to geosynthetic materials can strengthen the mechanical properties of the soil, and prefabricated components can effectively reinforce slopes. This article reviews the current application status of plant fibers in subgrade engineering. In comparison to other soil stabilization materials, plant fibers offer clear economic and environmental advantages. Nevertheless, they come with two drawbacks, namely restricted mechanical properties and excessive water absorption. Challenges such as technical standards, fiber dispersibility, and durability still exist in their application. In the future, the application of plant fibers in subgrade engineering will continue to expand. Through technological innovation and standard development, it will provide environmentally friendly and efficient solutions for sustainable subgrade construction.