Abstract: Solidification treatment of highly cohesive tailings is one of the important means for resource utilization. Highly cohesive iron tailings were taken as the object to carry out strength characteristic experiments of solidified tailings using high-calcium geopolymer to analyze the impacts of different dosages of chopped basalt fiber and dry-wet cycles. The micro-cementation behavior, unconfined compressive strength, and the response parameters after dry-wet cycles (strength, mass loss, and electrochemical properties) of the fiber-reinforced solidified materials were discussed. It is concluded that: 1) Adding fiber increased the strength. 0.5% was the optimal dosage (strength increased by 29.1%), which is equivalent to reducing the dosage of geopolymer by about 2%. 2) Fiber, hydration products and tailings were bonded by cementation and frictional occlusion. An appropriate amount of fiber could reduce pore connectivity and increase the capillary water holding capacity. 3) The dry-wet cycles destroyed the cementation, and the damage was stable after the sixth cycle. The fiber has no obvious advantage in improving the dry-wet durability of the solidified materials. The above results provide theoretical support and method reference for clarifying the strength characteristics and durability of solidified tailings.

Key words: highly cohesive iron tailings, chopped basalt fiber, high-calcium geopolymer, micro-cementation behavior, dry-wet cycles