【作者】 刘福明；

【导师】 王端宜；

【作者基本信息】 华南理工大学 ， 结构工程， 2010， 博士

【摘要】 长寿命沥青路面的实质就是路面在设计使用寿命期间不会发生结构性破坏,路面的损坏仅发生在路面的上层,维修时不需要进行结构性处理,只需将表层混合料铣刨,并换成等厚度的新混合料即可,维修十分方便;其理念应该是通过对沥青路面结构的优化,合理设置路面各结构层的位置和层厚,从而延长沥青路面使用寿命,使其成为长寿命和较低维修成本的路面结构。而我国近些年来随着道路荷载的不断增加,特别是重载交通对我国的沥青路面提出了新的挑战。按传统的路面设计体系和设计标准设计的路面通常不到设计年限就出现了损坏,经常需要进行大修,由此造成交通的拥挤或堵塞,给高速公路、城市间的重要干道造成极大的压力。因此,为了提高高速公路沥青路面的整体质量,减少路面的维修,提升公路路面服务水平,降低原材料消耗,节约能源资源,提高公路的经济社会效益,并为沥青路面结构设计提供一定的理论参考。本文在对我国现行沥青路面结构分析的基础上,对影响长寿命沥青路面结构性能的参数指标、损伤破坏形式进行研究;应用有限元方法分析了长寿命沥青路面的结构响应及其损伤行为,并应用多尺度模拟方法进一步从材料角度分析研究沥青混合料的损伤演化行为。结合国内外长寿命沥青路面设计思想提出了沥青路面结构寿命匹配设计理念,并按照结构寿命匹配设计理念来研究优化我国沥青路面结构,从而使其满足长寿命路面要求。首先从沥青路面结构类型及损失破坏形式分析出发,分析研究了影响沥青路面损伤的指标和参数,提出了长寿命沥青路面的主要损伤破坏形式。沥青混合料动态模量参数是长寿命沥青路面结构设计中非常关键材料设计参数,在对一些先进的沥青混合料动态模量预测模型比较的基础上,利用沥青混合料动态模量试验实测数据对动态模量预测模型进行了验证,并提出了合适的动态模量预测模型。对沥青路面疲劳预估模型进行了比较验证,通过应用材料连续损伤原理确定了长寿命沥青路面设计的理论基础-沥青混合料的疲劳极限。针对传统弹性层状体系理论路面设计的路面响应通常在弹性层静载条件、圆形作用面积、均匀荷载分布及线性材料特征基础上用静载方法来计算与实际路面受力状态不符的问题,结合有限元方法,采用了瞬时轮载的隐式-动态分析原理,并考虑动态荷载对路面响应的影响来研究不同轮载、不同温度及不同速度下的路面响应,并研究了不同沥青路面结构的应力应变行为,同时分析了长寿命沥青路面的损伤行为。分析表明:厚沥青层路面结构具有较好抗损伤能力,其车辙损伤要小于较薄沥青层结构,在一定程度上,沥青层厚度的增加,对沥青混合料车辙损伤并没有大的影响;Top-Down裂缝不是始于路表面而是发生在沥青结构层里面的浅深处,且最有可能始于胶浆结合力较弱或路面温度较高的时候,也即对车辙敏感的混合料同样也对裂缝敏感,而在低温时出现Top-Down裂缝的可能性较小,甚至不会出现;轮胎-路面接触应力的均匀分布假设低估了临近路表面的路面破坏潜力,尤其是在高温时。应用细观力学多尺度模拟理论从沥青混合料材料角度分析了其损伤行为,对进一步理解长寿命沥青路面中的主要破坏形式Top-Down裂缝损伤成因具有一定的理论价值。最后结合我国沥青路面结构实际状况,用结构寿命匹配理念对我国沥青路面结构进行分析,认为半刚性基层沥青路面通过各结构层寿命的合理匹配,通过更换材料、改变厚度及变化层位等方法的优化,能够达到长寿命路面要求。本文取得的主要研究成果将为改善我国沥青路面结构设计、提高沥青路面整体质量,从而延长沥青路面使用寿命奠定坚实的理论基础。更多还原

【Abstract】 The essence of long life asphalt pavement is that the pavement would not occur structural destroy during the design service life of a pavement. The upper layer of the pavement is the only part that would damage, so pavement maintenance will be more effective as it only need to renew the destroyed upper layer of the pavement without structural repaired treatment. The theory of long life asphalt pavement should depend on the optimization of asphalt pavement structure, layers location and thickness to extend the life of asphalt pavement and reduce the maintenance cost. In recent years, the asphalt pavements of our country face with the challenge of the increasing pavement loading, especially the heavy loading traffic. Basic on traditional design system of pavement structure, the pavement would be destroyed before the design service period and need major repair. It leads to traffic jam and increases the traffic pressure of the highway and urban arterial road. In order to enhance the total quality of the highway asphalt pavement, reduce the pavement maintenance, upgrade the pavement service, cut down the consumption of material, save the energy, increase the economy and society efficiency and make contribution to the asphalt pavement structure design theory. This paper, basic on the analysis of asphalt pavement structure of our country, research on the parameter indexes and forms of damage and failure which effect the life of long life asphalt pavement, the structure response and the damage behavior of long life asphalt pavement by applying FEM, damage evolvement of asphalt mixture by multiscale modeling method from material science point of view. Combining with the idea of long life asphalt pavement at home and abroad, it raises the asphalt pavement life matching theory, optimize the asphalt pavement structure of our country by this theory and make it meets the requirement of long life asphalt pavement.Base on types of asphalt pavement and destruction forms, indexes and parameters which infused the deterioration of asphalt pavement were analyzed. According to the result, several forms of long life asphalt pavement destructions were put forward. A suitable model for dynamic modulus prediction was proposed to determine the design parameters of long life asphalt pavement; this model was base on the comparison and analysis among several advanced prediction models and on the verification of prediction model using test data from a dynamic modulus experiment of asphalt mixtures. The asphalt pavement fatigue prediction model was validated by comparing. The fatigue limit of asphalt pavement was determined based on the elastic-viscoelastic theory of asphalt mixture.In traditional pavement design, base on the theory of elastic layered system the calculated results were different from an actual pavement in condition of elastic layered static load, in the shape of action area, in the load distribution and in the assuming of material characteristic. The stress-strain behavior of different types of asphalt pavement were analyzed and the damage mechanism of long life asphalt pavement was analyzed at the same time, using transient loaded implicit-dynamic FEM and the pavement response of dynamic load in different load states, different temperatures and different speeds were considered. The result indicated that thick layer asphalt pavement possessed better damage tolerant, whose rutting depth was less than thin layer asphalt pavement. To some extent, with the increasing of pavement thickness, the thickness of pavement could play less important role in the properties of rutting. Top-down crack was not generated in the surface of a pavement but in the shallow layer of a pavement structure, and the most favor states for Top-down crack was when the mixture possessed weak bonding and in high temperature. According to the result, a mixture that was sensitive to rutting also sensitive to cracking. But it was not possible for Top-down crack be generated at low temperature, or event none. The assuming that the tire-pavement contact stress was uniform distribution could lead to a result that underestimated the damage of pavement in shallow layer, especially in high temperature.The theory of multi-scale simulate method of micromechanics was applied to analyze the damage behavior of asphalt mixture, which could help comprehending the cause of Top-down crack that was the main damage form of the long life asphalt pavement. In the last part of the study, the typical asphalt pavement structure in China was optimization analyzed basing on the idea of matching of structure life. It was considered that asphalt pavement on semi-rigid base could fulfilled the requirements of long life pavement by reasonable matching the service lives of each layer by optimizing materials and thickness.The major results obtained in the research would lay a solid theoretical foundation for asphalt pavement design, improve the overall quality of asphalt pavement and extend its life.更多还原