Research And Application Of Base Course Materials Of Guizhou Electrolytic Manganese Slag Pavement

Metal manganese is mainly produced by electrolytic method.my country’s electrolytic manganese output accounts for 97%of the global output,and it is the world’s largest producer,consumer and exporter of electrolytic manganese.my country’s manganese ore is mainly distributed in the southwestern manganese triangle region.Among them,Guizhou Tongren has found about 708 million tons of manganese ore resources,ranking first in Asia.At present,the treatment method of electrolytic manganese slag is mainly landfill or stacking,which not only occupies a large amount of land,but also pollutes the ecological environment and endangers human health.It is also one of the important constraints restricting the development of my country’s manganese industry.With the mass production of electrolytic manganese slag,which contains toxic substances such as metal free manganese,ammonia nitrogen and other toxic substances,innocuous treatment and utilization of electrolytic manganese slag resources have become a major problem to be solved urgently.In traffic civil engineering,the use of solidified manganese slag as a pavement base material is one of the main research directions.Carry out relevant research on the performance of cement manganese slag stabilized crushed stone mixture,and obtain a series of parameters such as cement（curing agent）content and mixture ratio,which provide technical support for the application of manganese slag to pavement base.In this paper,relying on the scientific and technological project of the Guizhou Provincial Department of Communications,"Research on the Key Technology of the Harmless Treatment of Manganese Slag and Its Application in Highway Engineering",firstly,the physical and chemical properties of electrolytic manganese slag,mineral composition,leaching toxicity,etc.The effect of slag solidification,according to the relevant requirements of the current"Highway Pavement Base Construction Technical Regulations"（JTG/T F20-2015）,the cement manganese slag stabilized gravel mix design;and tested the unconfined compressive strength,splitting strength,Mechanical properties such as compressive elastic modulus.The effect of leaching pollutants from the base layer was analyzed by simulating rainfall for many years.The fatigue test was carried out on the cement manganese slag stabilized gravel mixture and the asphalt pavement structure of the cement manganese slag stabilized gravel base was recommended for the secondary roads in Guizhou.The physical and chemical index test shows that the electrolytic manganese slag has leaching toxicity and no gelation;the leaching test result shows that 25%-45%cement has a better curing effect on manganese slag,and the content of leached Mn2+and ammonia nitrogen is lower than the national standard limit;6%;The 7-day unconfined compressive strength of the cement dosage mixture can meet the specification requirements,and the compressive strength of the mixture increases first and then decreases with the increase of the manganese slag content,and the splitting strength decreases with the increase of the manganese slag.The fatigue test was carried out on the mixture containing 15%electrolytic manganese slag.The results showed that the cement manganese slag stabilized gravel base layer can meet the road durability requirements in terms of fatigue life.The column leaching test results show that the leaching pollutants from the cement manganese slag stabilized gravel base layer are lower than the national standard limit when simulating rainfall for 20 years,but Mn²⁺appears to increase in 15 years.According to the combination of soil foundation strength and different traffic volume in Guizhou area,the reasonable thickness of cement manganese slag stabilized gravel mixture for secondary roads in Guizhou area is 30cm-40cm.