Study On Performance Of Iron Tailings Sand And Stone Aggregate Asphalt Mixture

With the rapid development of China’s industrialization,a large amount of mineral resources are consumed.As a kind of waste after beneficiation,iron tailings material is the main component of industrial solid wastes.Aiming at the large amount of iron tailings,large potential safety hazards,serious environmental pollution,Features such as low utilization rate,this research successfully applied it to asphalt mixtures,which not only reduced the use of natural aggregates,but also consumed a large amount of iron ore tailings.It is of great significance to economic society,environmental protection and sustainable development strategy.Firstly,the paper conducts experimental research on the basic properties of iron tailings’apparent morphology,density,water absorption,and mechanical indicators.The chemical composition and phase composition of iron tailings are analyzed by means of ICP-MS mass spectrometer,EDS energy spectrometer,and XRD,which confirms the feasibility of iron tailings replacing conventional aggregates.Secondly,due to the high Si O2 content of iron tailings,the adhesion to matrix asphalt is insufficient.Consider using high-viscosity SBS modified asphalt or adding anti-stripping agents to improve the adhesion of iron tailings to asphalt.Based on the surface energy theory,the adhesion work between the mineral and different asphalts was calculated.The results show that after the SBS modified asphalt is used,the adhesion improvement of iron tailings is significant.Compared with 90~#matrix asphalt,the adhesion work is improved by 14.5%on average.After adding anti-stripping agents,the adhesion is better,but the increase in adhesion work is not obvious.Then,three groups of mineral mixtures with similar passing rate of each sieve are designed by different mixing proportion of materials.The content of iron tailing stone and iron tailing sand is 75%and 2%respectively.The influence of Fe O in iron tailing on the volume stability of asphalt mixture is tested by water swelling test of asphalt mixture and leishijia method.The results show that the iron in the tailings does not adversely affect the volume stability of the asphalt mixture under its natural content.Finally,the Marshall Test,high temperature rut test,and low temperature bending test were used to evaluate the high and low temperature performance of iron tailing asphalt mixture.The water immersion Marshall Test,freeze-thaw split test and Hamburg rut test were used to comprehensively analyze the water stability of the iron tailing asphalt mixture.The results show that under different asphalt binder,the high and low temperature performance of the iron tailing asphalt mixture can meet the technical index requirements.The incorporation of iron tailings has no significant effect on the high temperature performance of the mixture.The iron tailings have a positive effect on the low temperature performance of the asphalt mixture,and the low temperature performance is improved more significantly after the SBS modified asphalt is replaced.After taking measures to improve the adhesion,the residual stability and TSR indicators have been greatly improved.The addition of anti-stripping agents has significantly improved the water loss resistance of the iron tailing asphalt mixture during the creep phase,and the asphalt mixture has been eroded by water during the spalling The rate of stripping damage is not much different.As far as the improvement effect is concerned,SBS asphalt(plus anti-stripping agent)>90~#(plus anti-stripping agent)>SBS asphalt,Dynamic viscoelastic properties of the iron tailings asphalt mixture were analyzed by dynamic modulus test using SBS modified asphalt as the binder.The results show that the dynamic modulus index of asphalt mixture meets the requirements of technical index,and the dynamic response characteristics of load are significantly affected by temperature and loading frequency,high content of iron tailings can reduce Temperature sensitivity of asphalt mixtures.In summary,the iron tailing asphalt mixture has excellent performance,which verifies the feasibility of the iron tailing sand stone material to replace the traditional aggregate.