Research On Crack Resistance And Blocking Property Of The Flexible Interlayer Of Asphalt Pavement

Reflection crack and shear slide of interlayer are familiar disasters of semi-rigid base asphalt pavements, they not only affects road appearance and riding comfort, but also shorten pavement service life excessively. However, having a flexible interlayer between surface course and base course is an effective way to solve the problem. By doing mechanics analysis and laboratory test, this paper makes a study of road ability and construction method & technique of some flexible interlayer.Applying fatigue- fracture mechanics theory and method, this paper analyses the mechanism of semi-rigid base reflection crack and puts forward calculational methods of stress intensity factor of reflection crack; By using Ansys, this paper studies the influence of parameter varieties of interlayer to the stress intensity factor with vehicle load, temperature load and coupled load. Result of analysis makes clear that flexible interlayer have good effect on dissipation of the stress intensity factor; it can also restrain or delay expansion of reflection crack. After choosing appropriate indices of crack resistance, this paper does correlative laboratory tests to compare low-temperature crack resistance of rubberized asphalt, SBS asphalt, epoxy asphalt and emulsified asphalt interlayer. Result of the test indicates rubberized asphalt and SBS asphalt are good at crack resistance.The paper makes research on blocking property of interlayer: brings forward impact factor of adhesive strength of interlayer based on adhesive strength theory; designs water stability test of interlayer and advances indices of water stability for interlayer; compares impact on shear stress of surface module, base module, modular ratio of surface course and base course, base thickness and surface thickness by mechanics calculation; advances indices of shearing strength of interlayer by calculation, puts forward indices of pull strength with consult of criterion of bridge flooring; applying shear test and uplift test makes a compared study of blocking property of rubberized asphalt, SBS asphalt, epoxy asphalt and emulsified asphalt interlayer, the study includes to obtain the optimum content of the fourth interlayer, to analyses impact on shear and pull strength of temperature, immersion, positive pressure, etc. Using impermeability test checks up impermeability of interlayer. The result of test shows rubberized asphalt, SBS asphalt, epoxy asphalt are upstanding at blocking property, especially the rubberized asphalt and the SBS asphalt. The paper studies construction method & technique of interlayer, advances optimized construction procedure and evaluates operating effect of experimental road. Rubberized asphalt and SBS asphalt interlayer are suggested to be the appropriate interlayer of asphalt pavements eventually.