Lignin fiber is an organic fiber primarily used in road paving and serves as an indispensable stabilizer. Lignin fiber is usually fluffy, but in some cases, such as in Stone Mastic Asphalt (SMA) road surfaces, the lignin fiber used as a stabilizer is granular.

Lignin fiber is an organic fiber obtained through chemical treatment of natural wood, with a fluffy appearance in white or grayish white. It is processed through screening, splitting, high-temperature treatment, bleaching, chemical processing, neutralization, and screening into fibers of various lengths and thicknesses to meet the needs of different materials. Due to its processing temperature exceeding 250°C, it is chemically very stable under normal conditions, not corroded by common solvents, acids, or alkalis. It boasts excellent qualities of being non-toxic, odorless, pollution-free, and non-radioactive, affecting neither the environment nor human health, making it a green and environmentally friendly product—a feature not found in other mineral fiber types. The microscopic structure of the fiber is strip-like, uneven, porous, with flat intersections, offering good toughness, dispersibility, and chemical stability, strong water absorption, and excellent thickening and crack resistance properties.