非均布轮载、层间界面及粘弹效应下沥青路面结构组合研究

A rational structural combination, namely the combination of the thickness and modulus of each layer of the asphalt pavement, is the basic guarantee to make sure the enough life-span of asphalt pavement. In the current structural combination design methods of the asphalt pavement, only the design principles are emphasized, there is no substantive content. At the same time, as for the most popular asphalt pavement structure design methods, they are for determining the thickness of a special layer rather than for considering synthetically the combination of thickness and modulus for each layer, which should be based on the ability that resisting rutting, resisting the fatigue cracking and thermal cracking and top-down cracking and their propagation and so on. In addition, the mechanical responses in the asphalt pavement structure are strongly influenced by the tire-pavement contact pressure distribution and the interface layer characteristics. .In virtue of the results of dynamic resilience modulus test, interface characteristics test, anti-cracking test, relaxation test and wheel tracking test, this study will focus on the permanent deformation characteristics, fatigue cracking and top-down cracking and thermal cracking and their propagation characteristics, which are not only for the whole pavement structure but also for each layer; hereinto, the measured tire-pavement contact pressure and the properties of layer interface will be involved. After that, based on the outcome of above researching, a proposed methodology for the structure design of optimizing structural combination of asphalt pavement will be recommended; farther, a Nomogram will be plotted for the relationship among the cumulative amount of loading axis and life-span and the combination of thickness and modulus of each layer.

合理的路面结构组合是保障沥青路面使用寿命的基本前提。目前的沥青路面结构组合设计方法主要是一些原则性的要求，并无实质性的内容；而已有的沥青路面结构设计方法，基本上只是进行某结构层的厚度设计，没有从抗车辙、抗疲劳开裂以及抗裂缝扩展等方面，综合考虑路面各结构层厚度与模量的合理组合问题，同时，没有合理的考虑实际轮胎荷载、层间界面、荷温耦合下沥青层应力应变特性及裂缝扩展特性等等。本课题将通过开展动态回弹模量实验、界面特性实验、抗裂实验、松弛实验和车辙实验，从荷载-温度耦合角度出发，探讨非均布轮载、层间接触以及材料粘弹性条件下，沥青路面整体结构和各层的变形特性、包括疲劳开裂和裂缝扩展在内的温缩裂缝、反射裂缝和Top-down裂缝的特性；然后以此为基础，提出沥青路面结构的合理组合设计，并建立路面使用寿命与各结构层厚度及模量组合的相关关系诺莫图，为沥青路面结构的优化和使用寿命的提高提供理论基础和应用依据。

合理的沥青结构组合是保障沥青路面使用寿命的基本前提。综合考虑实际轮胎荷载、层间界面、荷温耦合下沥青路面车辙和裂缝扩展特性。从荷温耦合的角度出发，运用动态回弹模量试验、动态模量试验、层间界面特性试验，获得沥青路面层间界面粘结特性参数和粘弹性参数，建立了沥青路面结构模型有限元模型，分析沥青路面结构内的变形特性和裂缝扩展特性，结合Overlay tester(OT)试验和Hamburg rutting 试验结果，获得了反射裂缝扩展模型和车辙预估模型。根据反射裂缝扩展模型和车辙预估模型分析了不同厚度和模量组合情况下的沥青路面裂缝扩展和车辙特性的疲劳寿命。从而得到沥青路面结构组合的基本方法和结构组合相关关系的诺莫图，为沥青路面的合理结构组合提供基本的理论支持和应用依据。