纤维增强乳化沥青碎石应力吸收层断裂性能研究

发布时间：2018-04-11 18:12

  本文选题：应力吸收层 + 乳化沥青　； 参考：《重庆交通大学》2014年硕士论文

【摘要】：在我国高等级公路建设中，主要采用半刚性基层加沥青混凝土面层的复合结构形式，该路面结构在运营期间容易因裂缝而出现各种病害，在交通荷载和温度荷载的作用下，半刚性基层裂缝向上扩展是形成反射裂缝。反射裂缝成为半刚性基层沥青面层最主要的破坏形式之一，选择合理的层间连接技术是解决这一问题的关键。在国外，纤维增强乳化沥青碎石应力吸收层作为半刚性基层与面层之间的应力吸收层已经得到了广泛的应用。 本文通过对应力吸收层结构、技术性能以及组成材料进行分析，得出该应力吸收层具有良好的应力吸收和分散能力；较高的防水性能；良好的高温稳定性；并且施工方便快捷。在复合材料及断裂力学理论的基础上，对纤维沥青碎石应力吸收层的应力强度因子及断裂韧性进行计算分析，探索纤维沥青应力吸收层在裂缝尖端应力下的阻裂行为规律。 以贫水泥混凝土水泥板代替半刚性基层，制作铺设纤维增强乳化沥青应力吸收层复合路面结构试件，模拟路面反射裂缝扩展形式。通过三点弯曲试验，测量模拟半刚性基层路面结构的断裂参数，以断裂能作为评价路面结构抗裂性能的指标，分析纤维增强乳化沥青应力吸收层的抗裂性能。得出，在相同试验温度下，纤维增强乳化沥青碎石应力吸收层复合路面的最大扰度大于改性乳化沥青透层复合路面的最大扰度；纤维增强乳化沥青碎石应力吸收层复合路面的最大弯曲力大于改性乳化沥青透层复合路面的最大弯曲力；纤维增强乳化沥青碎石应力吸收层复合路面的断裂能大于改性乳化沥青透层复合路面的断裂能。 进一步研究纤维增强乳化沥青应力吸收层复合路面结构断裂参数的温度关联性，选取25℃、20℃、15℃、10℃、5℃、0℃、-5℃、-10℃、-15℃、-20℃作为试验温度。得出：纤维增强乳化沥青碎石应力吸收层复合路面结构最大扰度值随着温度的降低逐渐减小；最大弯曲力随着温度的降低逐渐减小；断裂能随着试验温度的降低先增大再减小，当温度降低时，路面结构由粘弹性逐渐变为准脆性，弯曲力出现突变，由断裂能计算公式可知，断裂能与力与扰度曲线围成面积相关，，所以使得断裂能的变化规律性降低。
[Abstract]:In the construction of high grade highway in our country, the composite structure of semi-rigid base course with asphalt concrete surface layer is mainly adopted. The pavement structure is prone to various diseases due to cracks during operation, under the action of traffic load and temperature load.The upward propagation of the semi-rigid base cracks is the formation of reflective cracks.Reflection crack has become one of the main failure forms of semi-rigid base asphalt surface layer. The key to solve this problem is to select reasonable interlayer connection technology.Fiber reinforced emulsified asphalt macadam stress absorption layer has been widely used as a stress absorption layer between semi-rigid base and surface layer.Through the analysis of the structure, technical properties and composition of the stress absorption layer, it is concluded that the stress absorption layer has good stress absorption and dispersion ability, high waterproof performance, good high temperature stability, and easy and fast construction.Based on the theory of composite material and fracture mechanics, the stress intensity factor and fracture toughness of the stress absorbing layer of fiber-asphalt macadam are calculated and analyzed, and the crack resistance behavior of the stress absorption layer of fiber asphalt under crack tip stress is explored.The semi-rigid base was replaced by lean cement concrete cement slab, and the composite pavement structure specimen with fiber reinforced emulsified asphalt stress absorption layer was made to simulate the propagation of reflective crack on the pavement.The fracture parameters of simulated semi-rigid base pavement structure were measured by three-point bending test. The crack resistance of fiber reinforced emulsified asphalt stress absorption layer was analyzed by taking fracture energy as an index to evaluate the crack resistance of pavement structure.At the same test temperature, the maximum disturbance of the composite pavement with fiber reinforced emulsified asphalt macadam stress absorption layer is greater than that of the modified emulsified asphalt permeable composite pavement.The maximum bending force of fiber reinforced emulsified asphalt macadam composite pavement is greater than that of modified emulsified asphalt composite pavement.The fracture energy of fiber reinforced emulsified asphalt macadam composite pavement is higher than that of modified emulsified asphalt composite pavement.The temperature dependence of structural fracture parameters of fiber reinforced emulsified asphalt composite pavement is further studied. 25 鈩

本文编号：1737116