A review of reactivity diagnosis, activation strategies, and engineering performance of low-reactivity mine tailings in alkali-activated materials

Mine tailings (MTs) are produced in large quantities worldwide and create long-term environmental and engineering burdens, while their silicate- and aluminosilicate-bearing phases make them potential resources for low-carbon alkali-activated materials (AAMs). However, their use in AAMs is often limited by low reactivity, strong heterogeneity, and variable engineering performance. Existing studies have reported activation methods, material properties, and application cases, but a framework connecting precursor characteristics, reactivity diagnosis, activation design, and application-oriented performance evaluation remains insufficient. This review addresses this gap by taking low reactivity as the central bottleneck of MT-based AAMs. It discusses the physicochemical origins of low reactivity, diagnostic methods for precursor assessment, barrier-specific activation strategies, and the relationship between engineering performance and practical applications. The review emphasizes that bulk chemical composition alone cannot determine precursor suitability, activation should be selected according to the dominant reactivity barrier rather than treatment intensity, and durability and leaching stability must be evaluated together with mechanical properties. Selected literature data show that activation and formulation design can markedly modify MT-based material performance: the activity index of molybdenum tailings increased from 58.7% to 78.7% after mechano-thermo-chemical activation, iron tailings reduced 90-day drying shrinkage by up to 58% as sand replacement, and optimized iron-tailings mixtures retained 94.53% relative dynamic elastic modulus after 80 freeze-thaw cycles. Overall, this review establishes a reactivity-diagnosis–activation-performance-application matching framework for transforming low-reactivity MTs into reliable low-carbon engineering materials.