沥青路面层间剪切疲劳性能研究

发布时间：2018-08-16 14:44

【摘要】：层间结合优劣是影响沥青路面使用寿命的重要因素之一,特别是在沥青路面大纵坡路段、小半径路段及加速制动区域等处,路面结构层将会产生水平荷载,当荷载重复作用超过一定次数以后,路面结构内产生的剪应力就会超过强度下降后的抗剪强度,使沥青路面出现疲劳破坏。近年来,因新型的双层摊铺技术具有明显改善层间粘结性能等优势而在我国兴起,但相关研究主要集中在对国外技术方法的借鉴消化及其对路面力学相应的影响,并未研究该种摊铺方式的疲劳性能。基于此,本文就目前现存的两种路面摊铺方式进行了层间剪切疲劳性能的研究,以此分析两种摊铺方式下的疲劳性能。首先,本文对江西昌九高速以及国道318落凼至分水段进行了沥青路面病害调查,在此基础上分析了路面可见病害的损害程度与层间损坏程度的关系。结果表明:两者间没有直接的联系,在路表出现严重病害时层间只是出现裂缝,而路表出现单一裂缝时,层间界面却已断裂;行车道病害处芯样与同桩号路肩处的芯样相比可以看出,路面病害与车轮荷载反复作用产生的疲劳破坏相关;车辙与裂缝的出现几乎都伴随着层间界面的滑移,甚至断裂。其次,利用45°斜剪试验,就两种摊铺方式下成型的试件进行了层间抗剪强度及层间剪切疲劳试验,对其剪切疲劳性能进行了研究。结果表明,沥青混合料剪切疲劳试验数据体现了良好的三阶段变形趋势,能清楚的解释路面层间的永久变形;分析了疲劳寿命、层间抗剪模量及剪切变形率三个指标,认为疲劳寿命仅从数值上就可以直观清楚的知道疲劳性能的差异,并不能反应疲劳性能与材料性能的关联性;层间抗剪模量随荷载作用的变化存在三个阶段变化趋势,但是荷载作用后期拐点的出现与否存在许多不可控因素,并不是所有的沥青混合料试件都会出现明显的拐点,因此,以层间抗剪模量值表征层间剪切疲劳性能仍需大量的试验进行进一步验证;稳定阶段的层间剪切变形(ND1)随荷载作用次数的增加基本上层线形增加,计算得到的ND1是个较为稳定的参数,可以用来表征不同层间状况下的剪切疲劳性能。最后,利用Bisar3.0软件确定了描述层间粘结状态的ALK的范围,并通过室内试验进行验证,认为ALK介于0~2之间,为层间界面处于较好的粘结状态;上面层与中面层层间粘结的缺失对沥青层底产生的压应力,不会产生自下而上的疲劳裂缝;并且弯沉控制模式下的疲劳寿命比以层间剪应力控制模式下的疲劳寿命多了50倍左右。因此,进行沥青路面设计不考虑层间剪应力的影响是很不安全的。
[Abstract]:Interlayer combination is one of the important factors that affect the service life of asphalt pavement. Especially in the large longitudinal slope section of asphalt pavement, small radius section and acceleration braking area, the pavement structure layer will produce horizontal load. When the repeated loads exceed a certain number of times, the shear stress generated in the pavement structure will exceed the shear strength of the asphalt pavement after the strength decreases, which will cause fatigue damage to the asphalt pavement. In recent years, the new double-layer paving technology has become popular in China because of its obvious advantages of improving the interlayer adhesion. However, the related research mainly focuses on the reference and digestion of foreign technology and methods and its corresponding influence on pavement mechanics. The fatigue performance of this kind of spreading method has not been studied. Based on this, this paper studies the interlaminar shear fatigue performance of the two existing pavement paving methods, and analyzes the fatigue performance of the two paving methods. Firstly, the paper investigates the asphalt pavement diseases of Changjiu Expressway and 318 National Highway from Lutai to Waterway, and analyzes the relationship between the damage degree of visible pavement diseases and the damage degree between layers. The results show that there is no direct relation between them. When there is serious disease on the road surface, only cracks appear between the layers, but the interlayer interface breaks when there is a single crack on the road surface. Compared with the core sample at the same pile and the same pile, it can be seen that the pavement disease is related to the fatigue failure caused by repeated wheel loads, and the occurrence of ruts and cracks is almost accompanied by the slippage and even fracture of the interlayer interface. Secondly, the interlaminar shear strength and interlaminar shear fatigue tests were carried out by 45 掳oblique shear test, and the shear fatigue properties of the specimens were studied. The results show that the shear fatigue test data of asphalt mixture show a good three-stage deformation trend, which can clearly explain the permanent deformation between the pavement layers, and analyze the three indexes of fatigue life, shear modulus and shear deformation rate. It is concluded that the fatigue life can know the difference of fatigue performance directly and clearly only from the numerical value, and it can not reflect the relationship between fatigue performance and material performance, and there are three stages of variation tendency of shear modulus between layers with load. However, there are many uncontrollable factors in the occurrence of inflection point in the later stage of loading, not all the asphalt mixture specimens will appear obvious inflection point, so, A large number of tests are needed to further verify the interlaminar shear fatigue properties, and the interlaminar shear deformation (ND1) in the stable stage increases with the increase of the number of loads, and the interlaminar shear deformation (ND1) increases with the increase of the number of loads. The calculated ND1 is a relatively stable parameter, which can be used to characterize the shear fatigue properties of different interlaminar conditions. Finally, the range of ALK describing the interlayer bond state is determined by using Bisar3.0 software, and verified by laboratory tests. It is concluded that the ALK is between 0 and 2, and the interlayer interface is in a better bond state. The compressive stress caused by the bond between the top layer and the middle layer will not produce the fatigue crack from bottom to top. The fatigue life under deflection control mode is about 50 times longer than that under interlaminar shear stress control mode. Therefore, it is not safe to design asphalt pavement without considering the effect of interlayer shear stress.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U416.217

【参考文献】