Abstract: To improve the crack resistance of pavement semi-rigid base, and promote the application and development of fiber cement stabilized base materials, the fiber types, physical and chemical properties were systematically combed, and the suitable length and content of fiber for cement stabilized base were determined. The mechanical properties and deformation characteristics of different types of fiber cement stabilized base were compared and evaluated, and the toughening and crack resistance mechanism of fiber cement stabilized base was further analyzed. The results show that, in terms of length and content, polyester fiber data is concentrated in 15~50 mm and 0.06%~0.08% (mass fraction), which are higher than other fibers. The mechanical properties and deformation characteristics of cement stabilized base modified by fibers have significantly improved. Among them, the 28 d unconfined compressive strength of the polyvinyl alcohol (PVA) fiber cement stabilized base has been improved by 6%~34%, and the average improvement in the 28 d splitting strength of the polypropylene fiber cement stabilized base and PVA fiber cement stabilized base is 30% and 18%, respectively. In addition, polypropylene fiber has the best effect on improving the dry shrinkage coefficient of cement stabilized base at 28 d, which can be reduced by about 18%~37%. The average reduction in the 28 d temperature shrinkage coefficient of PVA fiber cement stabilized base is 23%, and the data of 90 d temperature shrinkage coefficient is concentrated in 6%~22%, both at a high level. By analyzing the toughening principle of fiber cement stabilized base material, it can be seen that the fiber mainly weakens the internal stress concentration of the base through bridging effect and delays the development of cracks.

Key words: road engineering, fiber, cement stabilized base, mechanical property, deformation characteristic, toughening mechanism