Effect of different fibers and fiber contents on the mechanical properties and failure behavior of early age cemented lithium feldspar tailings backfill

The cemented lithium feldspar tailings backfill (CLFTB) samples with different fiber types and contents were prepared and subjected to uniaxial compression tests. The results show that glass fiber had the best improvement effect on UCS. With the increase in fiber content, the UCS showed a trend of first increasing and then decreasing, increasing from 1.138 MPa to 2.017 MPa and then decreasing to 1.907 MPa, with the optimal content being 0.6%. The relationship between the strength gain percentage (SGP) and the peak strain gain coefficient γ with fiber content was analyzed. As the fiber content increased, SGP first increased and then decreased while γ gradually increased. Fibers enhanced the ductility, peak load-bearing capacity, and dissipative energy required for the failure of CLFTB. Furthermore, showing greatly enhanced crack resistance in FRCLFTB, evidenced by an increase in the number of fine cracks and a decrease in fragment detachment.