| The total length of the coastal highway is over40,000kilometers. These highways are the important transport hubs connecting the coastal cities and ports. Frequent role of overload container vehicles has caused serious damage to the road surface evenness at coastal areas of asphalt concrete pavement, then the vehicle dynamic load caused by pavement unevenness will be further exacerbated the destruction of asphalt pavement, causing the asphalt pavement life dramatically reduced. Additionally, being often exposed in salt spray, the service life of the asphalt pavement in northern coastal areas is further reduced under the coupling effect of the deicing salt erossion and cycle of freezing and thawing during the long icing winter. Therefore, the study of estimated service life of asphalt roads based on unevenness and environmental effects of extreme flatness for northern coastal areas is an urging problem to solve.In this paper, the damage mechanism of asphalt pavement under vehicle load caused by road unevenness was studied firstly by theoretical analysis, field experiment and numerical simulations based on the research results at home and abroad. Then the low temperature flexural properties and fatigue characteristics of asphalt road in chloride ion penetration and freeze-thaw action coupling was studied. Finally, the multi-objective prediction model for asphalt pavement was built, based on this model, combined with practical engineering examples, the life of asphalt pavement under the condition of the roughness, chlorideion erosion and freeze-thaw was predicted, the main contents of this paper are as follows:(1) Based on the study of dynamic load caused by the uneven pavement for the pavement damage mechanism, translated the actual uneven pavement structure on the road into most unfavorable sinusoidal surface, and established a quarter vehicle model. Then the relationship between the wavelength, amplitude, and vehicle speed under a certain evenness was researched..(2) The three-dimensional finite element model of pavement structure was established by ANSYS program, based on the model, dynamic response of the pavement structures under the influence of different load and speed was studied. By constructing the pavement uneveness curve, and placing the stress and strain gauge displacement in different depth structure roughness pavement layer buried corresponding, the dynamic responsement of uneven pavement under different driving speeds and traffic loads was studied by the field experiment. Especially, the feature of pavement structure layers vertical stress variation with depth and speed was studied mainly. Finally the verification of accuracy of the finite element analysis model was done.(3) Specially considering the extreme environment using condition of asphalt pavement in the northern coastal areas, the low temperature performance test and fatigue test was performed for studying the effect of chlorideion erosion and freeze-thaw coupling on the performance of asphalt mixture on low temperature and fatigue characteristics, the bettering effect the basalt fiber on chloride ion erosion and freeze thawing effect of asphalt mixture under low temperature performance and fatigue characteristics was also studied.(4) Pavement multiple reference index prediction model was established, based on the prediction model, considering the adverse effects of dynamic load of surface roughness which caused by unevenness as well as the chlorideion corrosion and freeze-thaw coupling effect on the low temperature properties and fatigue characteristics of asphalt pavement, combined with the specific engineering, the service life of asphalt pavement of the typical coastal area of northern China was predicted. |
