Black and white interlaminar instability failure of asphalt overlay on old cement slab

In order to study the two kinds of instability failures between asphalt overlay and old cement slab such as black and white interlaminar horizontal shear slippage and interfacial bonding instability, the influence rules of vehicle speed, road adhesion coefficient, vertical load, interlaminar contact coefficient, loading rate, temperature and the spraying amount of viscous oil on interlaminar extreme stress and strain, shear strength and pull-out strength were revealed through the elastic theoretical calculation of composite structure, MATLAB programming, interlaminar shear test and pull-out test.The function relationships among interlaminar shear strength and normal stress, shear rate, temperature, and among pull-out strength and pull-out rate, temperature, the spraying amount of viscous oil were established respectively.Analysis result shows that the descending order of pull-out failure interface occurrence probabilities at 15 ℃ is cement slab surface, tack coat, asphalt membrane, the descending order at 45 ℃ is tack coat, cement slab surface, asphalt membrane, and average interlaminar bonding strength increases with the descending of above order.In order to reduce interlaminar instability failure, vehicle speed should be increased appropriately, vehicle axle load should be controlled, the clean and rough surface conditions of old cement slab should be kept, the spraying amount of viscous oil should be chosen appropriately, liquid petroleum asphalt is 0.20-0.40 L·m^-2, and emulsified asphalt is 0.48-0.60 L·m^-2.The average pull-out strength of core sample and interface failure position are recommended as distinguishinging bases for the construction quality of asphalt overlay.