The Causes And Dispose Of Reflective Crack On Old Cement Pavement Floored With Asphalt Concrete Overlay

Asphalt concrete overlay on the old cement concrete pavement is a practical andeffective way of rebuilding old cement pavement, It not only makes full use of theresidual strength of the cement concrete pavement, but also has the advantages of lowcost, ease of application, and little influence on environment and traffic near and playsa great advantage at the early stage of the pavement. But as the old pavement platebetween the joint or crack under seasonal environment temperature and repeatedvehicle load, it is easy to form the reflection crack. The emergence of reflective crackseriously affecting the performance of the pavement is a big threat on the durability.So how to take effective measures to prevent and control the emergence anddevelopment of reflection crack is the key to the paper.The following aspects are studied:Firstly, the stress-absorbing layer of asphalt overlay structure load stress analysesis conducted. Bottom stress of overlay stress-absorbing layer structure based on theABAQUS three-dimensional finite element model establishment burdened drivingloads is analyzed. The deflection amount, deflection difference changed with overlaythickness, stress absorbing layer thickness and stress absorbing layer modulus aregained. Directly overlaid structure stress-strain relationships were compared andanalyzed.Secondly, the stress-absorbing layer of asphalt overlay structure thermal stressanalyses is conducted. Bottom stress of overlay stress-absorbing layer structure basedon the three-dimensional finite element model establishment burdened thermal load isanalyzed. The deflection amount, deflection difference changed with overlaythickness, stress absorbing layer thickness and stress absorbing layer modulus aregained. Directly overlaid structure stress-strain relationships were compared andanalyzed. Studies show that: reflective crack protection works when adding asphalt overlaythickness in a certain range; additionally, stress absorption layers paved betweenAsphalt concrete overlay and old pavement pane can lessen the occurrence andexpansion of reflective cracks positively and gained the optimum thickness2cm～3cm.