Mechanical Property Modulation Mechanisms and Strengthening Strategies for Lightweight Thermal Insulation Refractories: A Review

Lightweight thermal insulation refractories (LTIRs) face an inherent trade-off between thermal insulation and mechanical integrity under harsh, multi-physical service environments. However, existing research largely focuses on isolated strengthening techniques and lacks an integrated understanding of multi-field coupled progressive degradation and synergistic design principles. Addressing this gap, this review establishes an integrative framework linking damage physics to full-chain strengthening strategies. We first delineate a three-stage progressive damage model under coupled thermo-mechano-chemical fields, spanning microcrack initiation, corrosion-induced volume distortion, and creep-driven skeletal collapse. Subsequently, reinforcement breakthroughs are systematically evaluated across four complementary dimensions: pore micro-architecture engineering, pore-wall densification alongside bonding-phase reinforcement, multi-scale toughening, and heterogeneous interface engineering. Finally, to resolve intrinsic performance conflicts, we deliver actionable guidelines and a service-condition-based design map that synergizes pore spheroidization, in situ crystalline interlocking, and dynamic interfacial stress relaxation. This work provides theoretical guidance and a practical roadmap for the rational design of highly damage-tolerant, energy-efficient refractories tailored for extreme industrial conditions.