Preliminary Study On Road Performance Of Red Mud Based Soil Condensate Solidified Loess

The study of pavement structure layer materials with high strength,dry shrinkage and temperature reduction,and good durability has always been an important topic in the field of road engineering.As a new type of soil curing agent,soil condensate has potential research value in reducing dependence on natural sand and gravel resources,protecting the ecological environment,and reducing engineering costs in road engineering construction.At present,there are few researches on the performance of red mud based soil condensate solidified loess used in highway,its road economy and technology need to be studied in depth.In this paper,based on the red mud based soil condensate solidified loess subbase test road project of lu-jia-wan connecting line of er-che highway in Gansu Province was used to change the road.by studying the unconfined compressive strength,dry shrinkage and durability of soil condensate solidified soil,compare and analyze the road performance of condensate solidified soil and other types of solidified soil,and discussthe technical and economic feasibility of the application of the solidified soil to the pavement structure layer in highway engineering.The test results of physical and mechanical properties of red mud based soil condensate show that,the condensate used belongs to the silica-calcium cementitious material,which belongs to the non-clinker cement in the silicate dictionary.When the water-binder ratio is 0.4,the 3-day compressive and flexural strength of the soil-condensed rock pure mortar specimen is lower than the corresponding strength of the cement mortar specimen,but the increase in flexural and compressive strength is greater in 3-28 days.They are 143% and 318% respectively,which are much larger than 49% and 88% of cement paste.The test results of the solidified soil of the red mud based soil condensate and the strength performance of the comparative mixture showed that,the 7d unconfined compressive strength of condensed soil is higher than that of cement-solidified soil,and it is also higher than that of composite-solidified soil with stable materials such as cement and fly ash.The seven-day unconfined strength of soil condensate stabilized soil can reach 2.0-5.0MPa,and the technical requirements of each structural layer of the pavement can be met by adjusting the content.The durability test results of red mud based soil condensate solidified soil,cement solidified soil and cement stabilized gravel show that,preliminary test results show that the early water stability coefficient of condensed soil is slightly better than that of cement stabilized soil,and the opposite is true in the later period;the water stability is much lower than that of water stabilized gravel;the frost resistance of condensed soil is superior better than cement-solidified soil,but is significantly weaker than cement-stabilized gravel;the scouring quality integrity of soil-concrete soil is very close to that of cement-solidified soil,and the erosion resistance of soil-concrete soil is significantly weaker than Cement stabilized crushed stone;The shrinkage performance of condensate solidified soil is better than that of cement solidified soil.Regarding construction and test section validation,it is not recommended to mix the solidified soil on the road,plant mixing method should be chosen when conditions permit.Soil condensate modified soil(mixing amount 4%-6%)is not recommended to replace cement for the replacement of highway subgrades of various levels.Condensate solidified soil with a content of 10%-12% can be used in the secondary and lower road subbases in areas where sand and gravel are scarce.Pave the test section for the pilot test,summarize the relevant construction,ratio,and establish a quality control system.Added data support and technical guidance for further research.