This study aims to convert waste rock into sustainable building materials by using it as coarse and fine aggregates to prepare basalt fiber and steel fiber-reinforced concrete (BFRC and SFRC). The optimal dosages and reinforcement mechanism of fibers were determined through mechanical performance tests, P-wave velocity tests, slump tests, and SEM analysis. Experimental research shows that incorporating an appropriate amount of fiber can improve the performance of concrete, and all BFRC and SFRC specimens meet the strength requirements. The concrete achieves the best strengths with 40 kg/m³ of steel fiber and 2 kg/m³ of basalt fiber. Compared to the control specimens, steel fiber greatly improves tensile strength by 22.2% and flexural strength by 27.4%, and basalt fiber increases them by 20.2% and 17.4%, respectively. Although SFRC specimens exhibit higher strengths, the production cost and CO₂ emissions of SFRC are significantly higher, with 2.46 times and 1.21 times than that of BFRC. SEM analysis revealed that the incorporation of an optimal dosage of fibers resulted in a denser microstructure within the concrete matrix. Basalt fiber and steel fiber with high elastic modulus and tensile strength provide significant bridging effects and crack resistance. The uniform distribution of fibers forms a dense network structure, limiting the generation and propagation of microcracks, thereby improving the mechanical properties. Overall, the addition of basalt fiber in waste rock concrete may be a more favorable choice. Besides, this study provides a theoretical basis for the resource utilization of waste rock and contributes to promoting the application of waste rock concrete in engineering.

Tailings are solid waste generated during mining and mineral processing. Their tremendous accumulation not only encroaches on arable land but also pollutes the environment. Currently, tailings are considered a viable alternative to natural fine aggregates in concrete because of their suitable physicochemical properties. However, existing studies remain highly fragmented and often report inconsistent conclusions owing to the considerable variability in tailings mineralogy, particle morphology, and physicochemical characteristics. To date, a comprehensive synthesis linking these intrinsic properties to the fresh, mechanical, durable, microstructural, environmental, and economic performance of tailings concrete remains lacking. Therefore, this review provides a systematic and critical assessment of tailings as aggregate in concrete and proposes an integrated framework connecting tailings characteristics, microstructural evolution, engineering performance, and sustainability outcomes. It systematically examines the physico-mechanical properties, durability, microstructure, hydration characteristics, environmental impact, and economic benefits of the resulting tailings concrete. The results showed that although tailings varied considerably in particle size, chemical composition, and mineralogy, they typically exhibited a rough surface texture and high water absorption. Furthermore, partial substitution of fine aggregates with tailings was found to improve the physical–mechanical properties and durability. However, to prevent performance decline, the substitution ratio should not exceed 50%. These benefits originated primarily from the filling effect and optimized particle packing, which increased matrix density. Microstructural analyses indicated that moderate tailings contents refined the pore structure, strengthened the interfacial transition zone (ITZ), and promoted hydration. In contrast, excessive substitution ratios weakened bonding and increased porosity. From an environmental perspective, the use of tailings generally reduced carbon emissions (by up to ~28%) and production costs (by up to ~50%) by lowering natural resource consumption and enabling large-scale waste valorization. Overall, tailings represent a sustainable aggregate alternative, provided that substitution levels are carefully controlled to balance workability, performance, and durability.