The Rational Position And Thickness Of Semi-rigid Base In Asphalt Pavement

In our country, about eighty percent to ninety percent of highways is the asphalt pavement, 95% of which using semi-rigid material as the base. It is the many advantages of semi-rigid base that provide the reliable guarantee for the pavement structure with strong base and thin surface. But for the early destruction, the road service life is reduced to a great extent. Therefore, it is necessary to set up necessary structure, reasonably arrange the semi-rigid base layer, and determine its reasonable s thickness to have good service performance.With the soft wares of BISAR3.0 and PADS, make mechanical analysis to the semi-rigid base asphalt pavement. Using orthogonal test method, when the semi-rigid as different layers, analyze and control the mechanical responses such as stress, strain and deflection under different combinations of traffic classification, base thickness and modulus and soil modulus, then analyzes on the related service performance—rutting and fatigue life. Based on the above, put forward three kinds of asphalt pavements. Structure I is with the traditional semi-rigid base, structure II is with graded crushed stone as a transition layer and the structure III is with asphalt treated base as the upper base. By comparison of the mechanical performance, the later two are better. So putting the semi-rigid base lower has theoretical basis and practical significance.Given the thicknesses of the surface course, asphalt treated base and graded crushed stone, put forward the structure forms adapting to traffic volume. After analyze the relationship between mechanical indexes and thickness of semi-rigid base or semi-rigidity subbase, and carry out tentative calculation of pavement structure thickness, the thickness of semi-rigid materials is determined. .