• Aggregate segregation in cemented coarse aggregate backfill is nonlinearly influenced by solid concentration and cement-to-aggregate ratio, with critical thresholds at 81–82 wt% SC and 10–12.5 wt% C/A.
• Uniaxial compressive strength (1.75–12.65 MPa) correlates linearly with SC and C/A but not with segregation degree; however, lower segregation (standard deviation <1.63) indicates higher elastic modulus.
• Segregation intensifies differential deformation and failure: top regions crack earlier, bottom regions are more compressible, and local strain differences reach 515–1693.70 με during stable deformation.
• Extreme aggregate unevenness accelerates crack penetration, leading to premature macroscopic tensile failure, which is critical for backfill design and stability in mining operations.