| With the rapid development of the national economy,the heavy-duty traffic in automobile transportation has greatly increased,which has aggravated the formation and development of rutting,cracks,subsidence and other diseases on asphalt pavements at all levels,seriously affecting the anti-skid,durability and safety of roads.High-performance durable pavement structures continue to emerge.Ultra-high-performance concrete composite asphalt pavement(RUHPC+AC)is a new type of composite pavement structure that combines the ultra-high strength and ultra-high toughness of road ultra-high-performance concrete slabs with the driving comfort of AC.RUHPC is mainly used as a load-bearing layer.AC is mainly used as functional layer.RUHPC+AC pavement structure has good overall mechanical properties,long service life,low maintenance cost,and low economic and reasonable premise.It will be one of the development directions of heavy-duty traffic durable pavement structure in the future.In this paper,according to the design requirements of advanced highway asphalt pavement,taking the thickness and modulus of each layer of the pavement structural layer as the analysis factors,64 groups of RUHPC+AC structural schemes are designed by orthogonal test.The pavement model was established by Mpave software,and four design indexes,such as the deflection of the road surface,the horizontal tensile strain at the bottom of the asphalt layer along the driving direction,the shear stress in the asphalt layer and the shear stress at the bottom of the asphalt layer,were calculated for 64 groups of structures.The value range of each parameter and the location of the maximum value.According to sensitivity analysis and multiple linear regression analysis,the variation laws and fitting formulas of each design index and each structural parameter are obtained.The mechanical analysis shows that the thickness and modulus of RUHPC,the thickness and modulus of base,and the modulus of sub-base and soil have a significant influence on the selected four design indicators,which are negatively correlated;the thickness and modulus of asphalt layer,the thickness of sub-base have positive and negative correlations with the four design indicators at the same time;reasonable parameter design can make the RUHPC+AC structure have good mechanical properties.Considering the interlayer interface characteristics of RUHPC+AC,SBS modified asphalt and epoxy resin were selected as binders,and composite specimens were made by wheel rolling method,static pressing method and Marshall compaction method.The effects of different binders and specimen forming methods on the interlaminar shear strength and interlaminar tensile strength of RUHPC+AC composite specimens were investigated experimentally.The experimental study shows that the shear resistance of the epoxy resin interface adhesive is better.The order of the interface bonding effect of the specimen molding method is: Marshall compaction method > wheel rolling method > static pressing method,In this paper,the Marshall compaction method is selected as the composite specimen forming method.In order to increase the interface bonding force between the RUHPC+AC layers,the roughened bonding surface of the rock-socketed structure was experimentally studied.It increases with the increase of the particle size of the inlaid stone,and increases first and then decreases with the increase of the spreading area.The optimal stone inlay interface is9.5～13.2mm in size,50% in the spreading area,and the depth of the embedded stone is 1/2 of the particle size.Carry out the comparative test of different interface bonding methods of RUHPC+AC,and the research shows that the adhesive bonding surface has lower shear strength,higher tensile strength and higher flexural tensile strength than the optimal stone-inlaid bonding surface,each with its own characteristics. |
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