Study On Structural Transformation Design Method For Asphalt Pavement With Semi-rigid Base

With the asphalt pavement in China have moved into a period of large and mediummaintenance, in the reconstruction and extension projects, can convert the structuralperformance of corrupted semi-rigid asphalt pavement? In the conditions of lower cost andsmaller social impacts, solve the compatibility issues of the pavement structure, improve thedurability of the pavement structure. This has a very important significance for the cause ofChina’s highways and even national economic development.This paper first analyzed the semi-rigid asphalt pavement damage forms and their causes,put forward to the method of semi-rigid base asphalt pavement structural conversion usingcold recycling technology, and proposed evaluation indicators of determining the coldrecycling maintenance scheme combined with <Highway Performance AssessmentStandards>: Pavement Quality or Performance Index（PQI）, Pavement Structure StrengthIndex（PSSI） and Core samples of the road full-face.By the mechanical response analysis of cold recycled asphalt pavement, theoreticallyverified the excellent mechanical properties of cold regeneration layer as the pavement base.Based on fatigue experimental results of emulsified asphalt mixture and foamed asphaltmixture, studied the variation of cold regenerative asphalt pavement tensile stress at thebottom of the grass-roots layer under the effect of axle load at all levels through finite elementmethod.Calculated the axle load conversion index of5.0through the fatigue equivalentprinciple.Through the comprehensive analysis of pavement structural design specifications ofasphalt pavement, based on the main failure mode of asphalt pavement, put forward topavement structural design specifications of cold recycling asphalt, that is deflection, tensilestrain of asphalt layers and tensile stress of cold regeneration layers.Based on three-layer structure system of asphalt layer--cold regenerationgrassroots--foundation （load-bearing layer under）, setting up orthogonal test including thethickness of asphalt layer h₁（m）,the modulus of asphalt layer E₁（MPa）, the thickness of coldregeneration grassroots h₂（m） and the modulus of cold regeneration grassroots E₂（MPa）,calculated by the finite element software to fit the formula of design specifications corresponding to different equivalent modulus E_t of foundation surface.Summarizing the research results of the full text, proposed the design method ofsemi-rigid base asphalt pavement structural conversion using cold recycling technology, anddrawn a specific design flow chart.