Effect Mechanism Of Asphalt Functional Interlayer On Rigid Pavement Early-age And Service Performance

Concrete pavement slab often broken prematurely under heavy load. Recently some scholars recommend that setting asphalt interlayer between surface course and base course to improve mechanical property of rigid pavement. But the existing theories still fall behind engineering practice.Therefore, the paper plan to research the influencing factors of asphalt interlayer’s working mechanism through numerical analysis of the mechanical behavior at early-age and service period and field full-scale slab test. Detailedly, including the research of mechanical behavior at early-age and sensitivity to parameter of pavement with asphalt interlayer, compare the difference of early-age character of pavement slab setting asphalt interlayer or not, the influence of the parameters of interlayer to early-age character of concrete pavement slab, the influence mechanism of the season of construction to asphalt interlayer at early-age and the working mechanism at early-age and service period of asphalt interlayer consider vehicle load. Finally based on the full-scale slab test to further analysis and verify of theoretical results. Specific conclusions are as follows:The warping deformation of the asphalt dissection slab in front of 72h are mainly composed of plate corner warping, after 72h as the growth of the elastic modulus, a quarter of the pavement plate, plate in place only to participate in warping deformation,and the emergence of cavity beneath slab. Early age stress increases with the age growth, and plate angle and plate stress variation is not consistent, the top and bottom of the plate corner performance in tension or compression at the same time, and the early age compressive and tensile stress at the top and bottom of the plate occurred in the reverse.Compared with ordinary board, angular displacement of the warping board after setting asphalt dissection significantly reduced, but the amount of warping of the plate is significantly increased. Meanwhile, the early age tensile stress of panel will significantly reduce,after setting the asphalt dissection.The shear stress of bottom plate mainly influence by plate warping,the more the amount of warpage board, the greater the shear stress at the end board.Compared with the interlayer thickness and modulus, increasing of interface tangential stiffness gives rise to the significantly increasing of early age pavement plate voids warping, but significantly reduces the amount of warping in the board. And increasing of modulus of elasticity, thermal expansion coefficient, poisson’s ratio of material parameter values also will give rise to the significantly increasing of the warping and stress of early age pavement plate. And parameters of creep compliance decrease will significantly reduce the early age road slab warping and slab bottom shear stress.After considering the effect of interlayer parameters on the interface contact stiffness,the smaller thickness,smaller modulus and smoother contact interface will make the warpage small in the plate angle and large in the plate center.However,the increase of interlayer thickness and modulus have little impact on pavement tensile stress in early age,but will significantly reduce the shear stress under the pavement slab and early interface cracking risk.In the four seasons,the pavement with interlayer and ordinary one constructed in early summer are quiet different in early age warpage and stress.compared with other places of pavement slab,the center part contributes the buckling deformation earlier and the warpageis larger than that of ordinary plate.Compared with ordinary plate, under the coupling effect of vehicle load and the early age characters, load performance of asphalt interlayer structure is obviously more negative. In the early age properties, the amount of warping and warping morphology are mainly factors significant influence on coupled stress, the influence of early ages stress is small. In addition, the rough interface resistance to overload transportation performance better.Finally, through full-scale plate test found that after setting asphalt interlayer, pavement slab area easily arch, however the edges of the plate more easily under the pressure, the early age stress of pavement slab is lower after setting asphalt function interlayer, maintained between 0.5-1.4MPa. The comparision between finite element calculation results and test results shows cement concrete pavement behaviour during early age is very complex, the effects of creep, shrinkage and interlayer performance during early age should be considered deeply.