Study On Shearing Fatigue Property And Evaluation Of Interlayer Contact Condition Between Base Course And Surface Course For Semi-rigid Base Asphalt Pavement

The domestic and foreign experts found that poor contact between base layer and thesurface layer of pavement structure was an important reason causing damage to the road early.In this paper, the research of interlayer contact condition between base and surface ofsemi-rigid asphalt pavement is conducted.In this paper, according to influencing factors of interlayer shear stresses, interlayershearing tests are made about different construction process. The change law of interfacerelative displacement, shear stresses, and shear elastic modulus along with time are researched.The method of judging interface fatigue life of different contact conditions is determined byinterlayer horizontal shear coefficient. Based on the multi-layer elastic layer theory, themethod of orthogonal analysis is adopted to analyze the effect of sensitivity of the pavementstructure parameters on various mechanical indicators with pavement structure under thetwo-round vertical loads, which interlayer contact state is completely continuous, horizontalforce state and completely smooth state between the surface and base. The impact maximumpavement structure parameters on interlayer shear and flexural stress of the bottom of theasphalt layer are determined. Based on the most sensitive structural parameters the law of themechanical response of the interlayer between surface layer and base layer, flexural stress ofasphalt layer bottom and semi-base layer bottom, interlayer shear stresses are calculated underthe different contact state.. The interlayer shear stresses and interlayer horizontal shearcoefficient and adhesion percentage are established, respectively. The approximate ranges ofthree kinds of interlayer contacts state are proposed.The state of interlayer completely continuous is simulated using the finite elementsoftware. Analyses of interlayer shear stress of simulating state and different treatmentprocesses showed that the value of η of the specimen with interlayer roughening, butinterlayer is still in part of contact state. That point of view is verified that the pavementstructure treated between interlayer is still in part of contact state.The result showed that the effect of mechanical response of pavement structure was verysignificantly with changes of interface condition between surface course and base course.Increasing the thickness of the asphalt surface course can reduce the interlayer shear stress todecrease shear stress under the condition of undestroyed the road structure caused by layerbottom tensile failure. Under the same interlayer shear stresses condition relativedisplacement of roughening specimen is smaller, the value of interlayer horizontal shearcoefficient is larger, the η value is also larger, fatigue life is the longest, the effect of interlayer adhesion is best.