Lignin fiber is an organic fiber primarily used in road paving as an essential stabilizer. It 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 light gray. It is processed through筛选 (screening), splitting, high-temperature treatment, bleaching, chemical treatment, neutralization, and screening into fibers of various lengths and thicknesses to meet the needs of different materials. Due to the high processing temperature of over 250°C, it is chemically very stable under normal conditions, resistant to corrosion by common solvents, acids, and bases. It boasts excellent qualities of being non-toxic, tasteless, pollution-free, and non-radioactive, affecting neither the environment nor human health, making it a green and environmentally friendly product—a characteristic not found in other mineral fiber types. The microscopic structure of the fiber is strip-like, wavy, uneven, and porous with flat intersections, demonstrating good toughness, dispersion, and chemical stability, strong water absorption, and excellent thickening and crack-resistant properties.