| In the completed freeway, the high class highway which used semi-rigid base material has been morethan90%. In winter, due to the weather is very cold in the northeast area, the asphalt pavements in theseareas will suffer from seriors freezing and thawing damage. With temperature decreasing and repeatlylaoding, the cracks will be happened on the semi-rigid bases and asphalt pavements, and usableperformance of pavements will be influenced. When the temperature rises, the frozen ice and snow willmelt quickly.It enters the structuer layers of pavements through the cracks and will cause the damage,suchas mud pumping，frost boiling. Under loading, pernetrable cracks will form the net shaped cracks and casuethe damage of pot holes or exfoliation.On the base of domestic and foreign related research results, enviormental and traffic character innortheast seasonal froaen soil region, this paper calculated pavement thicknesses of eight experimental roadstructures from the application status and damage models with asphalt pavement by the”HPDS” software.The results showed that eight structures can supply design requirement about deflection and bottom tensilestress. Considering the minimum requirements of antifreezing layer in northeastern region is from70cm to75cm,it will select70cm as the preliminary protocol structure. This paper analysised the mechanicalresponse by BISAR3.0software which concluded road surface deflection, the bottom maximum tensilestrain of asphalt layer, top vertical deformation of graded broken stone, compression strain on top ofsubgrade, tensile stress of semi-rigid base bottom and maximum shear stress of surface layer. Through theabove analysis, the scheme of pavement structure had been optimized. economical efficiency ofexperimetal road structures were analysised by the method of a life-cycle cost analysis Through the abovestudy, finally, the paper recommended four kinds of pavement structures as flexible base experimental roadstructures. |
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