Research On The Structure And Material Of AC+CRCP Composite Pavement

Because of the serious overload and heavy load, premature damage of highway is universal in many districts in China. Thus, it is urgent to propose proper pavement structure against heavy load traffic to improve the durability and long time performance of pavements. It is known that CRCP has higher bearing capacity and durability and that asphalt pavement has better riding qualities and is easy to maintenance. AC+CRCP composite pavement integrates the merit of the two kinds of pavement. It can provide better pavement performance for a long time under heavy load traffic. Structural damage would be avoided and only some slight maintenance is necessary for asphalt concrete overlay. Because China is abundant in cement resource but has a great shortage of petroleum deposits, studying this new kind of composite pavement is of strategic significance. Based on actual engineering item, the structural design, material evaluation and pavement performance of AC+CRCP composite pavement were studied systematically and comprehensively.Firstly, the structural design of CRCP was studied and the optimal structure was proposed according to the actual condition. A method for calculating the steel content of lug anchor terminal treatments was developed. The structure of wide-flange steel beam terminal treatment was analyzed by using finite element methods (FEM).Secondly, according to the characteristics and construction requirements of CRCP, the cement concrete design was studied. In order to improve the concrete performance, a concrete admixture composed of several parts of constituents was used. Construction considerations were also summarized from the practice.Thirdly, based on the result of FEM mechanics analysis for the tack coat interface layer, a kind of tack coat material with the best performance and the construction technics were recommended after a series of indoor and field experiments. The whole set of methods to choose proper tack coat material and to evaluate its performance was suggested.Fourthly, field surveys of the test roads were conducted, which lasted more than two years and included the development of transverse cracks and the slab movement of CRCP and thermal field of the composite pavement. Based on those survey results, the structure design and the performance evaluation were improved. A FEM simulation model was developed to predict temperature distributions of the pavement.At last, the long time performance of the pavement was studied by developing a rutting prediction model and economic evaluation.