【作者】 徐玮；

【导师】 王选仓；

【作者基本信息】 长安大学 ， 道路与铁道工程， 2007， 硕士

【摘要】 在车辆荷载和环境因素的长期作用下,水泥混凝土路面的路用性能逐渐衰变,当路面的使用性能(平整度、抗滑能力和承载能力等性能)降低到限定底线标准,或者其承载能力已不能满足交通需求时,可采用沥青加铺层修复,提高路面使用性能。针对旧水泥混凝土沥青加铺层结构的受力特点,本文建立多层体系有限元模型,对旧水泥路面沥青加铺层的破坏机理、力学特征以及寿命预估等问题进行深入研究,内容主要包括:(1)旧水泥混凝土沥青加铺层的破坏机理。针对加铺层的主要破坏形式,研究车辆荷载作用、温度变化诱发的剪切型、张拉型反射裂缝;(2)旧水泥路面沥青加铺层的工作状态研究,重点分析车辆荷载效应、温度效应以及荷载-温度耦合效应,考虑结构荷载响应随着不同影响因素的变化规律,分析铺设夹层对加铺层的应力消减作用;(3)沥青加铺层疲劳断裂寿命分析,根据断裂力学理论,分析荷载-温度耦合作用条件下,沥青加铺层底部裂缝尖端应力强度因子K_Ⅰ,K_Ⅱ,根据有限元分析确定裂缝扩展角和等效应力强度因子K_e,估算沥青加铺层的疲劳断裂寿命,进行加铺层结构参数敏感性分析;(4)进行室内疲劳断裂验证试验,较好的模拟车辆荷载对加铺层结构的作用,反映不同加铺结构层中反射裂缝的扩展过程,对比评价不同夹层材料在加铺结构中的阻裂效果。更多还原

【Abstract】 With the effect of vehicle loading and environmental influence, the performance of PCC pavement declined gradually. It wasn’t the time for AC overlay repaving until the service performance(toughness, skid-resistance and bearing-capacity et.) of PCC pavement degraded down to a specific level, or the existing pavement cannot satisfied the future transportation. The standard method of extending a pavement’s service life is to lay a new AC overlay over the old PCC. According to the unique structure of overlay composite pavement, the finite element methods and multi-layer system theory are adopted in the dissertation, which associated with deep research in damage theory, mechanic analysis and life-prediction mold of AC overlay on old PCC pavement. Here are mainly aspects in the study: (1)AC overlay pavement reflective-crack damage molds and theories. The initiating and propagating mechanism of reflective cracking is analyzed, and the influence of traffic loading and temperature variation were studied; (2)Mechanic analysis of AC overlay under the traffic-loading stress, thermal stress and the coupled stress. 3D FEM is used to analyze the AC stress in response to different structure parameters, through which the tendency of different parameters and relationships were illustrated The loading stress, thermal stress, and coupled stress in AC structures are emphatically analyzed considering the overlay structure with different interlay materials, which can greatly release the respond-stress of AC layer. (3)Crack analysis and life prediction mold of AC overlay. With fracture mechanic theory, the intensity factor K_Ⅰ, K_Ⅱin joints tip of AC pavement, are used to calculate expansion angle and equivalent intensity factor K_e, which were inputted into prediction mold of the fatigue life of asphalt overlay. After cracking-propagatation analysis, the reflective crack speed in different periods and fatigue life were obtained.(4)Lab experiments with asphalt concrete rutting test devices were applied to conduct fatigue reflective-cracking experiments, with comparison among different interlay materials in AC overlay structures. Rutting loading was used to simulate traffic-loading conditions, by which the initiating and propagating process of traffic-loading reflective cracking were simulated and further confirmate the theory calculations.更多还原