Composite Pavement With ISAC Mechanical Response And Structure Design

The composite pavement which is the structure of asphalt overlay pavement on the ce-ment concrete board can overcome the shortcomings of cement pavement and asphalt pave-ment, and include the advantages of both. The composite pavement can greatly improves the road performance because it has the rational stiffness, futhermore, it also can extends pave-ment's life. As the problems of cement concrete slab and the interlayers bonding, it must ef-fectively solve the problem of the reflective crackings before using the CC-AC composite pavement.Therefore, the paper studied the the compound road which set ISAC (Interlayer Stress Absorbing Composite, called ISAC) and discussed systematically the road's mechani-cal responses and the structural design method.This paper focused on unfavorable conditions of the partial load and low-temperature based on fracture mechanics theory, and analysed the ISAC advantages of preventing reflec-tive crack by calculating the stress intensity factor of the composite pavement which set ISAC or not at the most unfavorable position. It analysed mechanical responses of the com-posite pavement under the partial load and low temperature based on the Three-dimensional finite element models. The upper layer of ISAC is high modulus geotextile material, the mid-dle layer is the low modulus of vulcanized rubber asphalt, and the lower layer is the low modulus geotextile material.So it can take advantage of ISAC to delay the reflective cracks. This paper recommend the ISAC modulus of each layer.It compared the mechanical responses of the composite pavement which set ISAC or not under the partial load and low temperature condition, and further reflected the anti-cracked advantages of ISAC. It also analysed the in-fluences of factors to the mechanics of the composite pavement which include the overlay modulus and thickness,the slab modulus and thickness,the foundation modulus,the axle load,the air temperature.It analyzed the correction of partial stress and low temperature stress campared with the standard model when the factors changed. In the end, the paper proposed the structure design specifications, design standards and design methods of the composite pavement which set the ISAC, and also drawed the design flow, and recommended a reason-able pavement structure.