Interfacial Transition Zone in Rock–Backfill Composite Structures Under Thermal Action: Formation, Characterization, and Degradation

This review presents a systematic synthesis of the interfacial transition zone (ITZ) in rock–backfill composite structures under thermal action, focusing on (i) its formation mechanism, (ii) multi-scale characterization methodologies, (iii) thermally induced microstructural damage, and (iv) macroscopic interfacial mechanical degradation. A multi-tier literature retrieval protocol covering six databases (with foundational texts from 1945 and primary literature up to 2026) was employed to establish a rigorous core corpus. Furthermore, the micro-to-macro evolution laws under elevated curing temperatures, extreme high-temperature exposure, and freeze–thaw cycles are critically evaluated, and the limitations of current techniques and future research directions are discussed. This review provides a theoretical reference for ensuring interfacial stability in deep and special-environment backfill mining.