玻璃纤维格栅加强沥青路面

在热带或地处数个月夏季的高温地区或国家,车辙是沥青路面主要的破坏形式之一。车辙是由路面各层在反复荷载作用下产生不可逆变形累积形成的。众所周知,在引起车辙的各种因素中,沥青路面表面层的累积永久变形是最终沥青路面车辙深度的主要因素。因此,沥青混合料的抗车辙能力是一个在设计沥青混合料过程中必要且重要的因素。本文阐述了基于摩尔库伦理论玻璃纤维格栅加强沥青面层车辙预估模型的一系列研究结果:(1)较为全面地阐述了摩尔库伦理论在沥青路面的应用和发展,并指出运用摩尔库伦理论能够建立玻璃纤维格栅加强沥青面层剪切分析模型,而摩尔库伦模型能够很好地应用于沥青混合料设计和沥青路面结构设计的综合结构。(2)通过浸水车辙实验室试验研究了玻璃纤维格栅加强沥青面层在实验室高温潮湿条件下的车辙深度和相应的车轮碾压次数,试验考察了玻璃纤维格栅加强沥青面层厚度,玻璃纤维格栅拉伸强度和玻璃纤维格栅在沥青面层中的位置三个参量对沥青面层抗车辙能力的影响。(3)基于车辙是由致密(体积改变)和剪切变形(没有体积改变)引起的,而剪切变形比致密变形的影响大得多的车辙形成机理及广义基本能量等式,在考虑了荷载量级、荷载速度、荷载重复次数、路面温度、以及沥青混合料抗车辙的能力等影响沥青路面表面层车辙发展的主要因素的条件下,通过车辙试验获得车辙深度数据,采用有限元分析得出路面结构极限承载力和采用回归统计方法标定模型参数,从而建立了玻璃纤维格栅加强沥青面层实验室车辙预估模型。(4)路面设计的最终判断依据是路面使用性能,而路面性能参数测定值往往具有较大的随机性和变异性,为了能够深入了解玻璃纤维格栅加强沥青面层性能参数的特点,并为玻璃纤维格栅加强沥青面层评价、基于路面性能的路面设计方法和可靠度研究提供前期研究基础,提出了一种基于蒙特卡罗方法对玻璃纤维格栅加强沥青面层性能参数统计特性进行研究分析的方法。(5)采用有限元计算分析玻璃纤维格栅加强沥青面层结构组合的性能,根据分析结果指出运用玻璃纤维格栅可以大幅度地提高沥青混合料的抗剪强度,并能极大地提高沥青路面抗车辙能力。以此为依据并结合我国沥青路面设计规范中沥青路面设计流程,提出了玻璃纤维格栅加强沥青面层设计方法。
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Rutting is a major distress form found in asphalt pavements. Rutting is caused by the accumulation of irreversible (or permanent) deformation in all pavement layers under the action of repeated traffic loading. Among the contributions of rut depth by the various pavement layers, the cumulative permanent deformation in the surface course of asphalt pavement is well known to be responsible for a major portion of the final rut depth measured on the pavement surface. Therefor rutting resistance of a paving asphalt mixture is one of the important considerations in standard procedures for asphalt mix design.This paper reexamines potential usefulness of the Mohr-Columb concept for developing a rutting prediction model with geogrid reinforcement.(1) Past research has shown that the concept of Mohr-Columb concept can be applied for asphalt paving mix design. It has also been established that the Mohr-Columb concept is able to analyze the behavior of asphalt pavement with geogrid reinforcement by finite element analysis.(2) Immersion wheel tracking test for asphalt pavement with geogrid reinforcement is conducted in this study. This test was conducted to produce rut depth development data covering the parameters like the thickness of asphalt pavement surfacing, tension strength of geogrid and the placement of geogrid in the asphalt surfacing layer.(3) Many researchers abserved that rutting occurred as a combination of densification (volume change) as well as shear deformation (without volume change) , and the shear deformation rather than densification is the primary rutting mechanism. The model coefficients of the proposed rut depth prediction model based on power equation form include magnitude of traffic loads, loading speed, number of load repetitions, pavement temperature, and rutting resistance of asphalt mixture. They were determined by performing statistical regression analysis on the data derived experimentally and analytically from the rut depth development data in wheel tracking test and bearing capacity determined by finite element analysis.(4) The performance of pavement is the ultilty standard of pavement design, performance parameters of asphalt pavement is characterized by the inherent variability. It provides reference for evaluation of pavement perforcement、the design method of pavement based on pavement perforcement、and reliability of asphalt pavement with geogrid reinforcement. Thus, the approach for the statistic of the performance parameters in an asphalt pavement with geogrid reinforcement is illustrated in this study based on Monte Carlo simulation.(5) The structure composition for an asphalt pavement with geogrid reinforcement is analyzed and optimized by finite element method. It illustrates that the resistant of rutting in asphalt pavement is hightly increased by geogrid. The design for an asphalt pavement with geogrid reinforcement is proposed for the design method for specifications for design of highway asphalt pavement.