Design Research Of Dowel Based On The Load Transfer Performance Of Airport Cement Concrete Pavement

The civil airport cement concrete pavement common early appeared many diseases, such as subsidence, dislocation and other, which is caused by joints about 70%. Dowel bar settings improve the integrity and load transfer performance of the pavement structure to some extent, But with the increase of the number of aircraft loading, the bonding interface between pavement and dowel bar will produce some loose, causing attenuation of joint load transfer performance. Meanwhile the different levels of empty beneath pavement slab can also reduce joint load transfer capacity and structural properties of concrete pavement, leading to decrease service life. Therefore, the joint design is one of the key technologies in the airport cement concrete pavement engineering. In the current specification, the design of joint dowel bar only related with the pavement thickness, however, studies have shown that joint load transfer system affected by many factors, such as bond behaviors between surface and base, subgrade strength, aircraft loading and runway structural diseases and so on. At present, the relevant literature is less, and mostly limit to qualitative research, which does not involve practical design method that improve the joint load transfer capacity under the influence of multiple factors comprehensive. For that reason, the three-dimensional finite element model which considers interlayer contact and laboratory tests was adopted in the paper to analyze characteristics and load transfer performance of pavement structure, eventually establish joint dowel bar design method with considering many factors. Specific contents are as follows:Firstly, the three-dimensional finite element model of CCP which consider the different contact situations of dowel bar to concrete and surface to base was established by the ABAQUS finite element software. the influence rule of factors such as axel load, landing gear configuration, subgrade strength, bond behaviors between surface and base, the panel and dowel parameters on the pavement structure load transfer performance and concrete interface stresses was analyzed in the paper, further the change rule of the joint load transfer performance with empty beneath pavement slab and interface loosing and gives the suggested values of dowel diameter and spacing was studied.Then, based on the similarity theory and the saint venant principle, the doweled cement concrete pavement laboratory tests model were designed in the paper to research the displacement load transfer efficiency and mechanical properties of pavement joint concrete under normal working, interface loosing as well as empty beneath pavement slab conditions.Finally, based on the theory of orthogonal design, the sensitivity of influence facts on load transfer performance indicators was analyzed to establish the quantitative relationship of the main influence factors and the load transfer performance indicators. And on this basis, based on bradbury dowel checking formulas, the cement concrete pavement dowel design system was established by MATLAB program.The study contribute to systematically understand the load transfer mechanism of dowel bar, interface stress characteristics and distribution of pavement joints, and can provide a reference for the design and construction of the pavement and the dowel bar.