Concrete Rubblization Asphalt Overlay Pavement Structure Model Test

The existing cement concrete pavement with asphalt concrete over lay is the economical and fast way widely used in the highway or the reform of urban roads transformation in the new situation with the domestic oil industry rapid developed, and the product quality improved to conform the specifications, which promotes the improvement for the damaged cement concrete pavement used for number of years. For many years, the fatigue failure has been the focus of pavement engineering research as the major failure factor. Therefore, on the basis of previous studies, this paper analyzes the fatigue test of asphalt layer base load dynamic response characteristics and makes the preliminarily analyzing on the experimental results, through the experiment for fatigue of add a store structure of the full-scale model indoor in different rubblization degrees of asphalt, mainly including:(1)The full-scale structure model indoor test loads with a platform for the stress analysis of concrete rubblization asphalt overlay under the controlled environment, which is based on a reasonable model reflecting the objective reality. Considering the close relations between the technical requirements of rubblization and construction craft and according to the actual situation of experimental sites, vibrating compaction is adopted to make the secondary crushing plastic based on the pneumatic hammer broken concrete. The process of constructing mode indicates that the rubblization pavement based on the vibrating compaction and the pneumatic hammer can be completely with highway grassroots specification correspondence of aggregates flexible grassroots through the rational choice s.(2)Model test seeks a balance between under the precondition of practical and simplify the questions without violating the basic characteristics of structure.Due to the asphalt mixture with viscosity which makes time lag effect significantly on the stress response on the pavement overlay, the conventional stress and strain test methods cannot be used in accelerating fatigue test on the pavement. Therefore, designing of directly monitoring subsidiary, a static indirect test, dynamic test system satisfies the experimental analysis of demand for data collection capacity.(3)As the viscoelastic plastic materials, the viscosity of asphalt mixture significantly influences the deformation response of overlay, so with rubblization for grassroots, the response of overlay structures to the dynamic loads even more complicated not only with the location with load level related, also concerned. Out of the load plate direct action area, the long side direction parallel to the plate may be in the tensile while the side perpendicular to the plate may be compression; in load plate direct area, when amplitude for dynamic loads being 25KN, the bottom of pavement in the layer within the pull stress field; and amplitude for dynamic loads being 50KN, layer being in the state of alternative action of pulled compressive stress because of rebound, accelerating the overlay fatigue damage evolution process.(4)The overlay structures with rubblization concrete as grassroots obviously display the flexible layered structure characteristics under vertical stress. From the experiment results, the tensile stress of the bottom of pavement in load plate direct area is significant higher than outside the plate, the distance closer the more obvious strain response. Especially, the point monitored outside the load plate, tensile strain quantity increases very little with the increasing of accumulation of loads, but in load center place not only tensile the strain quantity increases with the numbers of load also the tensile strain rate shows the increase trend.(5)The rubblization degree of concrete slabs is the important factors to decide the function of the overlay structure. In the same load level and action frequency premise, the maximum tension stress on the bottom of overlay structures with high rubblization degree is less than low rubblization degree, and more attention should be paid to that concerning the unrecoverable tensile strain at the bottom of pavement overlay, the tensile strain rate with high rubblization degree increases significantly higher low rubblization degree. Above all, the fatigue resistance with the structure of high degree of rubblization is better than the structure of low degree.