Utilization of iron ore tailing as an alternative mineral filler in asphalt mastic: High-temperature performance and environmental aspects

Abstract

Excessive and unregulated stacking of iron ore tailing (IOT) has created numerous environmental issues, which has drawn considerable attention to focus on the resource utilization of IOT. The present study attempts to investigate the feasibility of IOT as a filler alternative compared to limestone filler, from the perspective of asphalt mastic. To achieve that, the physical and chemical properties for two types of fillers (IOT and limestone) were tested by the laser particle size analyzer, X-ray fluorescence as well as scanning electron microscopy. Four filler/asphalt weight ratios (0.6, 0.8, 1.0, 1.2) were then selected to prepare asphalt mastics. The rotational viscosity test, temperature sweep test as well as multiple stress creep recovery test were conducted to assess the high-temperature performance for asphalt mastics. Furthermore, environmental and economical aspects were evaluated by the leaching toxicity and cost-benefit analysis. Results show that the IOT possesses a smaller particle size and larger specific surface area than the limestone, which contributes to the adsorption of asphalt on the particle surface. As for asphalt mastics, the replacement of filler by IOT can greatly enhance the viscosity, rutting factor as well as percentage of elastic recovery, and significantly reduce the non-recoverable creep compliance. Further, IOT has no risk of large-scale use as building material based on the leaching results, and considerable economic benefits (benefit-cost ratio >1) can be obtained from the utilization process. Consequently, IOT has a promising potential as an environment-friendly filler to replace the mineral filler in asphalt mixture in view of the pavement performance and environmental aspects.