寒区沥青路面服役性能Ⅱ:疲劳寿命预估模型

Service performance of asphalt pavement in cold regionsⅡ:fatigue life prediction model

低温及冻融作用下的沥青混凝土开裂是道路工程中寒区沥青路面的主要病害形式之一。为量化寒区状态下这两类病害演化的影响,开展基于冻融分区下寒区沥青路面疲劳寿命预估模型的研究。首先,建立沥青混合料冻融损伤疲劳寿命衰变模型;然后,基于热量和降水指标进行冻融环境量化分区,根据损伤等效原则建立室内外冻融次数对应关系;最后,基于沥青混合料冻融损伤疲劳寿命衰变模型和室内外冻融次数对应关系,提出不同地区考虑冻融作用的调整系数计算方法。结果表明:对于不同地区,考虑冻结指数和考虑冻融的调整系数相对误差在20%以内;对于冻融频繁但低温不严重的地区,应当综合选取考虑冻结指数和考虑冻融的调整系数,以提高沥青混合料层疲劳寿命预估精度。研究结果可为寒区沥青路面疲劳寿命预估提供参考。

The cracking of asphalt concrete under the action of low temperature and freeze-thaw is one of the main diseases of asphalt pavement in cold area in road engineering.In order to quantify the effects of the evolution of these two types of diseases in cold zone state,the study of fatigue life prediction model of cold zone asphalt pavement based on freeze-thaw partitioning is carried out.Firstly,the fatigue life decay type of asphalt mixture freeze-thaw damage is established,secondly,the freeze-thaw environment is quantified and partitioned based on heat and precipitation indexes,and the correspondence between the number of indoor and outdoor freeze-thaws is established based on the damage equivalence principle.Finally,based on the fatigue life decay model of asphalt mixture freeze-thaw damage and the number of indoor and outdoor freeze-thaw correspondence,the calculation method of adjustment coefficients considering freeze-thaw effects in different regions is proposed.The results show that for different regions,the relative errors of the adjustment coefficients considering freezing index and freeze-thaw are within 20%.The adjustment coefficients considering freezing index and freeze-thaw should be selected comprehensively to improve the accuracy of fatigue life prediction of asphalt mixture layers.This study can provide a reference for the fatigue life prediction of asphalt pavement in cold areas.This study can provide reference for the fatigue life prediction of asphalt pavement in cold areas.