级配碎石基层与沥青混合料的层间粘结行为及其对路用性能影响研究

发布时间：2018-05-20 09:25

本文选题：级配碎石基层 + 层间粘结行为　；参考：《重庆交通大学》2015年硕士论文

【摘要】：级配碎石作为沥青路面的柔性基层,具有造价低廉、低温抗裂性以及水稳定性好等优点。然而级配碎石通常强度不高,与面层以及封层的粘结力不足,由此导致高温性能不佳且容易出现层间推移破坏,在实际应用中受到较大限制。因此,本文以“基于细观力学的级配碎石基层沥青路面层间粘结行为研究”项目为依托,在提高级配碎石基层强度的基础上,开展了基于室内足尺直剪试验和高温车辙试验的级配碎石柔性基层与沥青混合料的层间粘结行为及其高温性能研究。首先,论文以级配碎石强度理论为基础,级配碎石强度主要是通过抗剪强度来体现。通过控制关键筛孔以及粗细集料比例,设计出A、B、C三种不同粗细程度的骨架密实型级配碎石。在此基础上,通过CBR、回弹模量以及动力CBR等基础性能试验,对级配碎石柔性基层进行全面力学性能评价,得到不同粗细程度的骨架密实型级配碎石的排序依次为:B级配C级配A级配。接下来,为研究级配碎石的层间粘结行为,以抗剪强度为评价指标,采用自主研发的简易直剪仪进行级配碎石层与沥青面层的抗剪性能评价。首先通过材料性能检测,对集料、沥青等组成材料进行筛选测定;在此基础上,完成了柔性基层的路面结构的设计;然后,选取基层级配、封层厚度以及透层油量作为主要研究因素,进行三因素三水平的正交试验,结果表明:级配碎石基层对层间粘结行为影响最为显著,稀浆封层厚度次之,相比之下,透层油量对结果影响并不显著。基于以上试验,论文采用离散单元法,通过PFC2d数值软件进行直剪试验的仿真分析。第一步,进行贯入试验模拟,获取级配碎石微观性能参数;第二步,进行直剪试验模拟,以细微观角度描述级配碎石的相关力学行为,发现级配碎石体现出典型的散粒体特性,即整体的一致性以及个体的非一致性的统一。在此基础上,进一步调整模型参数,获取与室内足尺直剪试验拟合度较高的仿真模型。最后,进行级配碎石基层沥青路面高温稳定性的室内测评。采用车辙试验,同直剪试验一致,选取基层级配、封层厚度以及透层油量作为主要研究因素,进行三因素三水平的正交试验。结果表明:影响路面高温稳定性的因素依次为:级配碎石基层封层厚度透层油量。该结论与层间粘结行为的试验及仿真效果保持一致;并经过对比试验结果发现,级配碎石基层与沥青面层的层间粘结行为与其高温稳定性保持一种正相关关系。
[Abstract]:As the flexible base of asphalt pavement, graded crushed stone has the advantages of low cost, low temperature crack resistance and good water stability. However, the strength of graded macadam is not high, and the bond with surface layer and seal layer is not enough, which leads to poor performance at high temperature and easy to occur interlaminar damage, which is limited in practical application. Therefore, based on the project of "Research on interlayer bonding behavior of graded Macadam Base Asphalt pavement based on Meso-Mechanics", on the basis of improving the strength of graded crushed Stone Base, Based on indoor full-scale direct shear test and high-temperature rutting test, the interlaminar bond behavior and high temperature performance of graded macadam flexible base and asphalt mixture were studied. First of all, the paper is based on graded crushed stone strength theory, graded crushed stone strength is mainly reflected by shear strength. By controlling the key sieve hole and the ratio of coarse and fine aggregate, three kinds of skeleton dense grained macadam with different thickness degree were designed. On this basis, the mechanical properties of graded macadam flexible base are evaluated by the basic performance tests, such as CBR, modulus of resilience and dynamic CBR. The order of skeleton dense gradation is: B gradation C gradation A gradation. Then, in order to study the interlaminar bond behavior of graded macadam, the shear strength is taken as the evaluation index, and the shear performance of graded macadam layer and asphalt surface layer is evaluated by a simple direct-shear instrument developed by ourselves. First of all, through material performance testing, the aggregate, asphalt and other components of materials are screened and determined; on this basis, the design of pavement structure of flexible base is completed; then, the selection of base grading, As the main research factors, the thickness of sealing layer and the oil content of permeable layer were studied by orthogonal experiments at three factors and three levels. The results showed that graded crushed stone base had the most significant influence on interlaminar bond behavior, and the thickness of slurry seal layer was the second, in contrast, the thickness of slurry seal layer was the second. The effect of oil permeation on the results is not significant. Based on the above experiments, the paper uses discrete element method and PFC2d numerical software to simulate the direct shear test. In the first step, the microscopic performance parameters of graded crushed stone are obtained by the penetration test simulation. In the second step, the direct shear test simulation is carried out to describe the related mechanical behavior of graded crushed stone from a fine angle, and it is found that graded crushed stone exhibits typical granular properties. That is, the unity of the whole and the inconsistency of the individual. On this basis, the model parameters are further adjusted to obtain a simulation model with high fitting degree compared with the indoor full-scale direct shear test. Finally, the indoor evaluation of high temperature stability of asphalt pavement with graded macadam base is carried out. The rutting test is adopted, which is consistent with the direct shear test. The main research factors are the base level gradation, the sealing layer thickness and the oil content of the permeable layer, and the orthogonal experiments of three factors and three levels are carried out. The results show that the factors influencing the high temperature stability of pavement are as follows: the amount of oil through the sealing layer of graded crushed stone base. The conclusion is consistent with the experimental and simulation results of interlaminar bonding behavior, and it is found that there is a positive correlation between the interlaminar bonding behavior of graded macadam base and asphalt surface layer and its high temperature stability.
【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】：U414

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