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Macro‐synthetic fiber‐reinforced iron ore tailings (IOT) concrete is an environment‐friendly building material featured by recycling IOT and improving performance of IOT concrete due to fiber incorporation. In this study, the mechanical properties of macro‐synthetic fiber‐reinforced concrete incorporating IOT were investigated. Two different replacement ratios of IOT (i.e., 0% and 50%) and six types of macro‐synthetic fibers at 1.0 vol% were adopted to investigate the effects of IOT, aspect ratio, elastic modulus, and tensile strength of macro‐synthetic fibers on mechanical properties of concrete. The results indicate that the concrete with IOT for natural sand (NS) replacement in 50 wt% demonstrates no loss in compressive strength and a minor loss of 7.67% in fracture energy, but the incorporation of IOT lowers splitting tensile strength and limit of proportionality, especially the splitting tensile strength with a decrease of 18.50%. The splitting tensile strength, equivalent flexural tensile strength, residual flexural tensile strength, and fracture energy were notably improved by adding macro‐synthetic fibers. Experimental results using Tukey test and Student's t test demonstrated that the fiber aspect ratio was more effective in improving equivalent flexural tensile strength, residual flexural tensile strength, and fracture energy than the elastic modulus and tensile strength of fibers, and the residual flexural tensile strength fR,4 was enhanced by 146.34% when increasing the fiber aspect ratio from 36 to 60. [ABSTRACT FROM AUTHOR]

• The diamond-indent feature of MSF provides favorable interfacial bond strength. • MSF can compensate for the reduction in compressive strength caused by IOTs. • The fracture energy of IOT concrete increases by up to 20.19-fold due to MSF. • The relationship between the FRI and post-cracking behavior is developed. Iron ore tailing (IOT) is a hazardous by-product of iron extraction, and its disposal has resulted in serious environmental issues. This paper investigated the interfacial bond performance of macro-synthetic fiber (MSF). The effect of the IOT replacement ratio on the compressive performance of concrete and the effects of MSF on the compressive and flexural performance of IOT concrete were evaluated. Test parameters included IOT replacement ratio (0%, 50% and 100%), fiber volume fraction (0%, 0.5%, 1.0%, 1.5% and 2%) and fiber aspect ratio (43, 60 and 69). The test results indicated that the deterioration in compressive strength was observed with the increase in the IOT replacement ratio. The mechanism of the effect of IOT on the compressive performance of concrete was analyzed. However, the incorporation of MSF compensated for the reduction in compressive strength caused by iron ore tailings (IOTs). Furthermore, the post-cracking performance, which includes residual flexural tensile strength, equivalent flexural tensile strength and fracture energy, of concrete increased with the increase in fiber volume fraction. The fracture energy of IOT concrete increased by a factor of 18.06–20.19, and the post-cracking performance of IOT concrete was comparable with that of natural sand (NS) concrete at an MSF fiber volume fraction of 2%. At a given fiber volume fraction, the MSF with a higher fiber aspect ratio was more effective in improving post-cracking performance than one with a lower aspect ratio. Moreover, new empirical equations were proposed, which can accurately predict the residual flexural tensile strengths and equivalent flexural tensile strengths. These results provide important implications for determining the contribution of MSF in strengthening and toughening IOT concrete. [ABSTRACT FROM AUTHOR]

• The material characteristics of IOT are summarized. • The properties of IOT concrete are analyzed and compared with those of NS concrete. • IOT concrete has satisfactory workability, mechanical properties and durability. • The relationships between the mechanical properties of IOT concrete are established. • The application of IOT into concrete achieves sustainable development. Incorporating waste by-products in concrete is one of the critical approaches for sustainable development. Particularly, iron ore tailings (IOT) as ordinary industrial solid waste in China is discharged and deposited. This review is a recapitulation of the material characteristics of IOT and its effects on the workability, mechanical properties, and durability of concrete. The increasing development of ore beneficiation technology, along with the collection from various sources, results in the diversity of IOT characteristics. Owing to low pozzolanic activity, IOT is generally limited to substitute cement in concrete, so which need to be activated when partly replacing cement. Moreover, their high specific surface area and irregular shape have a detrimental effect on the workability of concrete; however, mechanical properties and durability exhibit different trends with increasing replacement of IOT in concrete. And we find that on the status of an appropriate replacement IOT can lead to a satisfactory workability, mechanical properties and durability of concrete. Based on previous research, we establish the fundamental correlation between mechanical properties. These conclusions can guide the application of IOT in concrete sustainable technology. [ABSTRACT FROM AUTHOR]