Study On Characteris Of Asphalt Overlay For Cement Concrete Airfield Pavement

During the construction and use of airports in our country, the cement concrete pavement is in the majority. Influenced by the plane load and external environment, the early part of cement concrete pavement has appeared various disease during middle and late period of operation, such as crack, rut, loose and so on. In order to maintain a good service pavement performance, re-paving asphalt concrete layer is a solution to problem of the old cement concrete pavement of airport. The traditional pavement design method of airport given little attention to the re-pavement of the old cement concrete pavement using asphalt concrete layer, the depth of re-pavement layer usually determined by the empirical approach used in abroad, with little prevention and solution to disease happened in re-pavement layer meanwhile. Therefore, it is of great practical significance and engineering application value to systematically research the design method of re-paving asphalt concrete on the old cement concrete pavement mainly for the mechanical properties of composite structures.This paper aims at the problem of asphalt overlay on old cement road surface, starting from the theoretical analysis, numerical simulation and indoor test to research performance of composite structures after re-paving, improving design methods of re-pavement layer. First, this paper investigates the existing situation of old cement airport to get statistics and analyzes the different types of diseases, combining with the feature of the airport pavement parameters and then giving out the design index of overlay, typical composite pavement finite element model will be constructed. Secondly, by analyzing the pavement mechanical response under different load condition, this paper calculates the location of the most unfavorable load, then the analysis of layer parameter sensitivity is undertook, the overlay depth design scheme will be determined. Thirdly, based on the Mechanical analysis results, the optimal design of paving layer asphalt mixture gradation will be determined, after analyzing the different gradation asphalt mixture according to improved re-paving asphalt concrete of airfield pavement design method which is combined with Marshall Method and Superpave Method. Then, it is considered in this paper that the external environment factors in the airport pavement, as well as the establishment of the finite element model of typical composite pavement temperature field and temperature stress field, to analyze the rule of airport pavement temperature and thermal stress distribution. Lastly, Combined with the interaction mechanism of the old cement concrete and re-paving asphalt concrete, and the consideration of the load stress and temperature stress of complex influence of the airport, this paper uses index corresponding different structural layer as design basis, to operate composite pavement design of airport and test.In conclusion, aiming at the problem of asphalt overlay on old cement road surface in airport, this paper finally gives out the calculation model, the control indexes and design grading of the overlay, systematically studies and summarizes the design and test methods of asphalt overlay on old cement road surface, which provides the reference in future design and construction of the asphalt overlay on old cement road surface.