Abstract: The resource utilization of iron tailings is an effective measure to reduce the risk of tailings inventory and save construction materials. Polypropylene fiber and glass fiber were used to modify cement stabilized iron tailings. The fiber content is 0, 0.25%, 0.5%, 0.75%, 1%, and the curing period is 7 days and 28 days, respectively. Fiber modified cement stabilized iron tailings (FCIT) was characterized by brittleness index, modulus strength ratio and toughness index. The mechanism of fiber was analyzed by SEM. The results show that the optimal content of glass fiber is 0.5%, while that of polypropylene fiber is 1%. Under the optimal dosage, the effect of glass fiber and polypropylene fiber on unconfined compressive properties of cement iron tailings is basically the same. Under the same fiber content, the unconfined compressive strength and toughness index of 7-day curing age are lower than that of 28 days, and the effect of curing age on the brittleness index of CIT is not obvious without fiber. The action mechanism of fiber on cement iron tailings can be divided into drawing, interweaving and agglomeration.

Key words: cement stabilized iron tailings, polypropylene fiber, glass fiber, unconfined compressive properties, composites