Application Of Straw Fiber Ultra-thin Wearing Course In Anti Sliding Treatment Of Tunnel Pavement

In recent years,the anti sliding treatment of cement concrete pavement in tunnel has become the focus of highway maintenance.In the treatment measures,the extra-thin wearing course has good wear resistance and driving comfort.In this paper,combined with the construction of the test section of zhonghechi No.1 Tunnel Pavement from white to black in Yizhou Hechi expressway,the treatment of anti sliding performance attenuation of cement concrete pavement in long tunnel by paving porous drainage ultra-thin wearing course is studied(1)High viscosity modified asphalt was prepared by adding high viscosity additives to SBS modified asphalt.The variation of penetration,ductility,softening point and viscosity at 60℃with different dosage was analyzed.The results showed that the optimal dosage was 8%,and the viscosity at 60℃reached 3.11×10~5PA·s,far exceeding the specification requirements of5.0×10~4PA·s when the dosage was 8%.Through the dynamic shear rheological test,it is concluded that the prepared high viscosity modified asphalt has good rheological properties.Through the micro mechanism research,it is shown that the high viscosity modified asphalt is physical miscible modification,and the high viscosity additives in SBS modified asphalt are agglomerated and cross-linked distribution.(2)Through the preparation of corn straw fiber,the optimal extraction rate and oil absorption ratio were obtained under the soaking time of 4 h.Through the microscopic test observation,it shows that corn straw fiber has large roughness,uneven surface,can absorb more asphalt,increase the internal friction of asphalt mixture and improve the performance of asphalt mixture,and then conduct performance comparison test with lignin fiber,it is concluded that the performance of corn straw fiber meets the specification requirements and its comprehensive performance is better than lignin fiber.(3)Based on the design idea of discontinuous gradation,the gradation is broken from 2.36mm to 4.75 mm.Referring to the gradation range of OGFC-10 and Nova Chip type-B,the special gradation design of straw fiber ultra-thin wearing course is obtained.Through the comparative test,the high temperature stability and water stability of asphalt mixture with 0.3%corn straw fiber are improved,and the anti sliding performance and water permeability meet the expected requirements.(4)Through practical engineering application,it is concluded that straw fiber ultra-thin wearing course is not only suitable for anti sliding treatment of cement concrete pavement in tunnel,but also has obvious advantages in cost,anti sliding and construction convenience,which has good economic and social benefits.