Utilization of waste rock from a low-carbon perspective: Mechanical performance analysis of waste rock-cemented tailings backfill

To promote low-carbon concepts, conserve resources, and enhance the utilization efficiency of waste rock (W R ) and tailings, this study investigated the mechanical performance and destruction characteristics of waste rock-cemented tailings backfill (WRCTB) under layered placement. Through uniaxial compressive strength (UCS) experiments to assess WRCTB specimens under different W R contents and grain sizes, accompanied by scanning electron microscopy (SEM) analysis of their microstructure. The results indicate that with an increase in W R content, the UCS of the WRCTB specimens gradually increased, with an optimal content of 50 %. Additionally, as the grain sizes of the W R increased, the WRCTB specimens’ UCS initially increased and then decreased, where the optimal grain size was 3–7 mm. Compared with the control group (N-WRCTB), the WRCTB specimens’ UCS showed a maximum improvement of 57.9 %. The WRCTB specimens exhibited higher total energy density, dissipated energy density, and elastic strain energy density, with the incorporation of waste rock resulting in a transition from brittle to ductile failure behavior, demonstrating more excellent toughness. Furthermore, the addition of W R altered the failure mode of the WRCTB specimens, shifting the primary failure mechanism from shear to tensile. Cracks developed from the mid-layer, leading to a multi-crack failure mechanism. This research provides valuable perspectives into the effective utilization of solid waste in mining and the design of WRCTB. • Using different waste rock contents and particle size. • The addition of waste rock increased the strength of WRCTB. • WRCTB was analyzed from the perspective of energy. • Waste rock changed the destruction characteristics of WRCTB.