Study On Regionalization Principle And Rational Structure Of Asphalt Concrete Pavement In Liaoning Province

With the rapid development of the transportation in China, technical progress is made continuously in highway construction and the technology system represented by semi-rigid base asphalt pavement theory has been formed and perfected. However, different kinds of premature failure and fatigue damage of the asphalt pavement has been occurring in different extents, more serious failure occurred in some highway sections indeed. It has reduced the road surface standard of service and has affected driving safety. Therefore, the study on the mechanics and controlling measures of premature failure has become one of the most important subjects in pavement research fields. A very important reason resulting in premature failure of asphalt pavement is that its structure type is excessively single. So, how the asphalt pavement can be adapt to the changes of its external environment is an urgent and complex problem to be resolved because its material and structural properties are very sensitive to the traffic loads and the external environment that varies with the changes of clime and time. By summarizing comprehensively the domestic and overseas successful and failing experience, this paper brings forward the basic analyzing method of the asphalt pavement structure, analyzes the pavement structure system characteristic of the already existing asphalt pavement in Liaoning province based on its damage characteristic and its corresponding environmental characteristic, conceives its regionalization index system and presents the regionalization principle based on the characteristic of the asphalt pavement structure system and brings forward the reasonable pavement structure in each region.According to the system theory, the essential idea and analyzing framework of the asphalt pavement structure system is conceived on the base of system unitary characteristic and environmental adaptability. It suggests the precondition which the asphalt pavement construction system can survive and develop is that the pavement could adapt to its environment around and traffic loads. The analytical framework has been built with system science thought and method on the methodology arrangement of ideas. Based on the comprehensive analysis of the technical data obtained by a large-scale survey of asphalt pavement performance as well as the data got before, taking Tieling to Siping, Shenyang to Shanhaiguan and Shenyang to Dalian expressway as representative section, the paper actually carries out lots of survey on natural environment, geological condition, volume of traffic, performance data, etc. and analyzes the data already existed data including construction and design. By analyzing its structural characteristic, its main failure forms and its cause, this paper has brought forward two principal asphalt pavement failure characters, namely, the early representative damage characteristic caused by water damages changing to the rut and the long-term structure performance losses such as Shenyang to Dalian expressway in use as representative. Referring to the domestic and overseas experience and abiding by the design principle of mutually coordinating and comprehensive balance, this paper indicates the two structures are indispensable through analyzing the advantage and shortcoming between semi-rigid and flexible base, in the meanwhile, the combined asphalt pavement structure and the compound pavement structure should be given priority to develop. The two stages developing conception on the combined asphalt pavement structure is brought forward for the first time. The analysis of large amount of data indicates that the determinant factor of the pavement strength attenuation is rainfalls intervals distributing. Considering Liaoning province is located in heavily seasonal frost area, average 20 days rainfalls intervals distributing before freezing has been adopted to be its asphalt pavement structure regionalization index to substitute the annual rainfalls index for the first time. Depended on the analysis of every reciprocal factors affecting the usage of asphalt pavement structure, the principle and the index system is conceived including interval rainfalls, high and low temperature index, freezing depth, traffic volume, etc.. The asphalt pavement structure regionalization and its corresponding rational structure types are brought forward. Furthermore, the sub-regionalization and its corresponding reasonable types are also brought forward. The paper suggests that the semi-rigid base pavemen structure should be mainly applied in the expressway in the western area of Liaoning province and combined pavement structure should be applied in the eastern area of Liaoning province.The research result of this paper has important academic significance to build the local guide of asphalt pavement rational structure for Liaoning province and has made necessary technology reserve for constituting suitable local specification for Liaoning provincial asphalt pavement.