Technical system, key scientific problems and technical frontier of long-life pavement

Abstract

The development of long-life pavement is the most effective means to reduce the resource consumption of road construction and maintenance. It can also relieve the traffic congestion which is caused by large and medium scale maintenance of pavement, and improve the road capacity and road network transportation efficiency. In this paper, the basic characteristics of long-life pavement were illustrated, and the current technology system of long-life pavement was introduced. The key technical problems and main scientific problems of the long-life pavement structure design, the design and development of durable pavement materials, and the pavement maintenance management and large and medium scale maintenance were analyzed. The results indicated that the pavement structure is a large scale spatial three-dimensional structure although it is simple in geometry. It is necessary to select three-dimensional elastic mechanics theory or even more complicated mechanical theory to analyze its mechanical response. The pavement materials exhibit the viscoelastic plastic characteristics, because most of the pavement materials use asphalt as binder. Therefore, only the visco-elastic- plastic mechanics theory can accurately describe the mechanical behavior of the pavement. Moreover, under the multi- physics coupling effects of temperature, humidity, ultraviolet rays and ice, snow, water, steam, the scientific problems inherent in the pavement structure are very complex. The material used for pavement is a kind of mixture with multi-phase, multi-scale, multi-component features. The micro-structure characteristics inside material, the micro-mechanism of load and load transfer, the damage evolution occurred and developed inside material, along with the corresponding relationship between them and the structural macro-performance parameters are extremely complicated. The performance characteristics of pavement material should be scientifically described as the guidance for the scientific design of the pavement material and the scientific analysis of the pavement structure. For this regard, some suggestions were proposed for the method of mechanical analysis, pavement structure design, the development of durability of road materials, and long-life pavement maintenance. For mechanical analysis and pavement structure design, the following researches could be conducted in future: (1) Constitutive theory of the multi-phase, multi-scale, multi-component materials; (2) strength theory and failure criterion of pavement materials under three-dimensional stress state; (3) fatigue failure criterion of pavement materials in three dimensional state; (4) spatiotemporal response characteristics and its evolution patterns of pavement structure performance under the coupling action of multiple physical fields; (5) robustness of sub-grade stiffness field and its relation to the mechanical behavior of pavement structure; (6) real time perception and information analysis of mechanical response characteristics of pavement structure during full scale test. As to the development of durability of road materials, the most efforts should be put into the modification of mix proportion design method of mixture, improvement of the durability of binder, and the study and development functional pavement materials. As to the long-life pavement maintenance, the most efforts should be put into theory and method about the timely perception, reflection and inversion of pavement structure performance, theory and technology about the fast perception of pavement performance, long term performance of pavement and the evolution model of the long term performance of pavement, the evaluation, prediction and intelligent decision-making of pavement performance, and technical principle and method of efficient utilization of reclaimed asphalt pavement. These researches provided direction for the development of perpetual pavements.