| The tensile stress at the bottom of asphalt layer was applied to the design specification inSpecification for Design of Highway Asphalt Pavement. For asphalt pavements withsemi-rigid base, the stresses at the bottom of asphalt layer are mainly either a lowcompressive stress or tensile stress. So it can be concluded that no damage will occur at thebottom of asphalt layer, which is contrary to the common cracking type. In order to make upfor the shortcoming of the design, the mixture design is optimized and the structural design ischanged, rarely do some change in the design specifications. Therefore, the relationshipsbetween the four strength indexes and pavement parameters and interlayer conditions areanalyzed using Bisar3.0program where the base layer is assumed to be an elastic layer, thesemi-rigid base is used to be the common base type. At the same time, the possiblerelationship between the four strength indexes and the pavement deformation and cracks, thedisadvantages and differences of different strength indexes which is applied to be the asphaltpavement design are speculated. Firstly, the Bisar3.0was employed to calculate the tensilestress and tensile strain at the bottom of the asphalt layer, the relationship between thedistance of center to center and the position of the peak value of tensile stress and tensilestrain is also studied. Secondly, in order to define the trends of road damage, the isoclines ofthe maximum shear stress are determined under the horizontal and vertical force. Theinfluences of the horizontal force and modulus of the wearing course on the position of themaximum shear stress are also investigated using bisar3.0. Finally, the variation and positionof distortional strain energy of asphalt pavement are analyzed with different wearing courseparameters and interlayer conditions. The formula to predict the value of the distortionalstrain energy was proposed. The research results are of reference value for the design andrepair of the asphalt pavement. |
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