Influence of fibers on the macro-micro properties of cemented tailings backfill

Uniaxial compression and scanning electron microscopy (SEM) analyses were conducted on cemented tailings backfill (CTB) specimens with varying fiber contents and lengths to investigate strength enhancement mechanisms. Results indicated a non-monotonic relationship between average uniaxial compressive strength (UCS) and both fiber content (optimal range: 12‰-18‰) and length. Optimal fiber content established hydration product-bridging skeletal frameworks to constrain crack propagation, while appropriately sized fibers enhanced plastic deformability through robust interfacial bonding without compromising load-bearing capacity. Fibers inhibited primary crack formation via bridging while providing nucleation sites for calcium silicate hydrate (C-S-H) and ettringite (Aft) to facilitate crack repair. During crack initiation, fibers anchored fracture surfaces, dissipated crack-tip energy, and restricted microcrack advancement.