Study On Mechanical Properties And Durability Of Iron Tailings Recycled Concrete Under Sulfate Dry-Wet Cycle

The living environment of human beings is seriously damaged by a series of environmental problems,such as the increasing discharge of iron tailings and the increasing waste concrete.In order to solve this problem,the research on recycling of waste concrete and iron tailings has been started in recent years.In this paper,the mechanical properties and sulfate resistance of recycled concrete with different content of iron tailings are studied when the replacement rate of recycled coarse aggregate is 30%.The main research work is as follows:(1)The mixture ratio of recycled aggregate concrete with iron tailing sand was determined by experiments,and then 264 test blocks were prepared.The mechanical properties and sulfate resistance of recycled concrete with iron tailing sand were tested.The results showed that the best aggregate ratio was formed when iron tailing sand replaced natural sand with 30% recycled coarse aggregate when the content of iron tailing sand was10%-30% As a result,the inner structure of concrete is more compact and the strength is improved.(2)Compressive corrosion resistance coefficient,mass loss rate and ultrasonic velocity are used as the evaluation indexes of the impact of concrete sulfate corrosion resistance.The results show that when the replacement rate of iron tailing sand is 30%,the mass loss rate is relatively low,the ultrasonic velocity value is relatively large,and the compressive strength is relatively large,which improves the sulfate resistance of recycled concrete with iron tailing sand,but its performance is slightly lower than that of natural aggregate.(3)According to the test results,by fitting the test data of recycled concrete with iron tailing sand,the calculation formula of the influence of iron tailing sand content on the mechanical properties and sulfate resistance of recycled concrete is established,which can be used for reference in research and application.