Research On The Development And Road Performance Of Self-compacting Rubber Granule-fluid Fly Ash Roadbed Filler

Highway construction often encounters high fill sections,reconstruction and expansion,and bridge and culvert abutment backfill sections in soft soil areas.The additional stress of the foundation of this section is large,and the roadbed construction face is narrow and difficult to compact.It is easy to cause uneven settlement after roadbed construction,causing engineering quality problems such as bridgehead jump.Lightweight unloading subgrade filler can effectively solve the above engineering problems,but the existing lightweight backfill materials generally have problems such as complex process and high cost,and there is no systematic understanding of the durability of the materials.It is urgent to develop new subgrade fillers.Based on the concept of solid waste recycling,this thesis uses waste tires and fly ash solid waste materials to develop a new type of self-compacting rubber particles-fluid fly ash roadbed filler with high fluidity,light texture,self-compacting,no need for rolling and vibrating,and high strength in the later stage.Solve the problem of seismic and frost resistance of roadbed,so that it has good durability.Through the combination of theoretical analysis,numerical simulation and laboratory test,this thesis aims to develop the best mix ratio of new rubber particle-fluid fly ash subgrade filler,clarify the influencing factors and changing rules of the durability of the new subgrade material,and explore the settlement deformation law of rubber particle-fluid fly ash subgrade.The following research contents are carried out:(1)Based on the orthogonal experiment,the mix design of new self-compacting rubber particles-fluid fly ash filler was completed.Firstly,the mixture ratio design of ordinary flow fly ash is studied,and based on this,the relevant factors affecting the road performance of rubber particle-flow fly ash subgrade filler are clarified,and the main test parameters affecting the mixture ratio design are determined(including rubber particle size and dosage,cement type and dosage,water dosage,admixture dosage,etc.).Based on the determined test parameters,the orthogonal test was designed to obtain the quantitative and qualitative relationships between the fluidity,compressive strength,modulus of resilience,density,shrinkage and other performance indicators of rubber particles-fluid fly ash and different test parameters.Based on the microscopic electron microscope,the strength formation mechanism of the new roadbed filler was revealed.(2)The durability of new self-compacting rubber particles-fluid fly ash subgrade filler was studied,and the optimal mix ratio was determined.Taking the compressive strength as the index,the water stability,dry-wet cycle stability,freeze-thaw cycle stability,thermal insulation and shock absorption test of rubber particles-fluid fly ash subgrade filler were carried out.The relationship between the durability of the new subgrade filler and the material mix ratio(including rubber particle size and rubber particle content)was established,and compared with the durability of ordinary flow fly ash without rubber particles.The durability evaluation of the new subgrade filler under the influence of different factors was obtained.Based on this,the optimal mix ratio under different working conditions was determined,which provided technical guidance for its engineering application.(3)The settlement deformation and stress distribution of rubber particle-fluid fly ash subgrade filler under the condition of only subgrade weight,overlying pavement and driving load are analyzed,and the settlement deformation law of the new subgrade filler is revealed.The three-dimensional numerical simulation software was used to establish the model and analyze the calculation.The settlement deformation and stress distribution of the new selfcompacting rubber particle-flowing fly ash subgrade under various working conditions were analyzed,and compared with the post-construction settlement of the subgrade backfilled with ordinary soil and ordinary flowing fly ash behind the abutment.