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Development of Structural Design Method of Ultra-Thin Whitetopping with High Strength Concrete

高强混凝土超薄白面结构设计方法的发展

基本信息

批准号：
17360206
负责人：
NISHIZAWA Tatsuo
金额：
$ 7.26万
依托单位：
Ishikawa National College of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-17360206/
关键词：
ultra-thin whitetopping ultra high strength fiber reinforced concrete bond strength 3d finite element method visco-elasticity accelerated loading test prefabricated concrete panel structural design ホワイトトッピング高強度コンクリート 3次元有限要素法付着試験

项目摘要

Ultra-Thin White-topping was originally developed in Northern Europe and America to rehabilitate severely rutted asphalt pavement Since then this method has been spread around the world. In Japan, this method has been tried in several sites as a trial and performance data have been collected. The performance data revealed that the white-topping structures is able to withstand at least medium traffic conditions for more than 5 years. On the other hand, Ultra High Strength Fiber Reinforced (UFC) has been developed and applied on several actual structures. Because-UFC has a very dense matrix and contains short fibers, it has excellent mechanical properties and durability compared with conventional concrete. Combining these two technologies, Ultra-thin white-topping structure with high strength concrete (HSCWT) was developed. In this method, 1.0m by 1.7m panels with a thickness of 30mm, which are prefabricated in a factory under very good curing conditions, are placed over an existing asph … More alt pavement The flexural strength of the HSC panels is more than 40MPa, which is much higher than normal concrete slabs. The panels are bonded with the asphalt layer by grouting the gap between them. For rational structural design of the HSCWT, mechanical behavior of the structure should be thoroughly understood. Although the HSC panels have very high flexural strength, the stresses in the panels due to traffic loads are expected to be very high and strongly depending upon the stiffness and thickness of the underlying asphalt layer. Furthermore, since the asphalt layer is much thicker than the panels, the visco-elastic nature of asphalt layer could not be ignored.In this study, in order to establish the structural design method for HSCWT, accelerated loading tests were conducted on full scale test pavement of HSCWT and long-term performance was investigated. 3DFEM analysis was performed to simulate the tests and address the structural features of HSCWT. Based on the analysis of loading tests and FEM calculations, a structural design procedure was discussed. The results of this study are summarized in the following.(1) Accelerated loading tests.Test pavements of HSC-WT were constructed on an accelerated loading facility and were subjected to moving axle loads about 150, 000 to 200, 000 times. From the test results, following remarks can be made :● Unbonded area developed from joint between panels, which might cause weak support for the panels and promote very fine surface cracking.● Stone and coin texture types on the bottom face of the panel effectively enhanced the bonding, while hole type of texture formed air void at the interface and weakened the bonding.● No serious problems under traffic loads raised on long term performance of HSCWT, as long as a sound bonding was ensured at the interface between the panels and the asphalt layer.● Joint reinforcement with underlying panels was not good measure.(2) FEM analysisBased on analysis of the loading tests with dynamic 3DFEM and comparison of the computer results with the measured data, visco-elastic parameters of the asphalt layer were identified. Mechanism behavior of HSCWT was investigated based on dynamic analysis of the loading tests with 3DEFM. Following remarks can be made :●For the summer loading test, low viscosity in the asphalt layer was identified, while for winter loading test, relatively high viscosity was identified.●Stresses in HSC panel was affected very little by visco-elastic parameters and loading rate. The most significant effect was the interface condition between the panel and grout.●Stresses in the panel much less than the strength of HSC panel if good bonding at the interface was ensured. Therefore the fatigue of the panel would not be an issue in the structural design of HSC-WT.(3) Structural design methodBased on the results of the accelerated loading tests and FEM analysis, a mechanical design procedure for HSCWT was developed. In the procedure, tensile strains in the underlying asphalt layer are calculated with 3DFEM and fatigue damage of the asphalt layer is estimated from the tensile strains using fatigue curve of asphalt mixture. It was found that not only viscosity of asphalt layer but also vehicle speed significantly affects fatigue life of asphalt layer. Less

超薄白顶最初是在北方欧美开发的，用于修复严重车辙的沥青路面。在日本，该方法已在多个研究中心进行了试验，并收集了性能数据。性能数据显示，白顶结构能够承受至少5年以上的中等交通条件。另一方面，超高强度纤维增强复合材料（UFC）已经在一些实际结构中得到了发展和应用。由于UFC具有非常致密的基体和含有短纤维，与常规混凝土相比，它具有优异的力学性能和耐久性。结合这两种技术，开发了超薄高强混凝土白顶结构。在该方法中，将在工厂中在非常好的固化条件下预制的厚度为30 mm的1.0m × 1.7m的板放置在现有沥青路面上 ...更多信息高强混凝土板的抗弯强度大于40 MPa，远高于普通混凝土板。面板与沥青层之间通过灌浆差距粘结。为了合理地进行结构设计，必须充分了解结构的受力性能。尽管HSC板具有非常高的抗弯强度，但是由于交通载荷而导致的板中的应力预计非常高并且强烈地取决于下面的沥青层的刚度和厚度。此外，由于沥青层比面板厚得多，沥青层的粘弹性性质不能忽略。在本研究中，为了建立HSCWT的结构设计方法，在HSCWT的足尺试验路面上进行了加速加载试验和长期性能进行了调查。采用三维有限元分析方法模拟了试验过程，并分析了高速螺旋桨的结构特点。在对加载试验和有限元计算分析的基础上，提出了一种结构设计方法。本研究的结果总结如下。(1)加速加载试验。HSC-WT的试验路面是在加速加载设备上建造的，并承受大约150，000到200，000次的移动轴载。根据试验结果，可以得出以下结论：●面板之间的接缝形成了未粘结区域，这可能会导致面板的支撑力较弱，并导致非常细微的表面裂缝。●面板底面上的石头和硬币纹理类型有效地增强了粘结，而孔类型的纹理在界面处形成了空隙，削弱了粘结。●只要确保面板和沥青层之间的界面处有良好的粘结，在交通荷载下，不会对高速水循环管道的长期性能产生严重影响。●与下面的面板进行接缝加固不是一种好的措施。(2)有限元分析通过动态三维有限元分析，并将计算结果与实测数据进行对比，识别出沥青层的粘弹性参数。基于三维有限元动力分析，研究了高强混凝土WT的力学行为。结果表明：●夏季荷载试验中沥青层的粘度较低，冬季荷载试验中沥青层的粘度较高。●高强混凝土板的应力受粘弹性参数和加载速率的影响很小。最显著的影响是面板和灌浆之间的界面条件。●如果确保界面处的良好粘结，面板中的应力远小于HSC面板的强度。因此，在HSC-WT的结构设计中，面板的疲劳不会成为问题。(3)结构设计方法根据加速加载试验和有限元分析的结果，建立了高速螺旋桨风力机的力学设计方法。在该过程中，在下卧层的沥青层的拉应变计算的三维有限元和沥青混合料的疲劳曲线的沥青层的疲劳损伤估计从拉应变。结果表明，沥青层的疲劳寿命不仅与沥青层的粘度有关，而且与车速有关。少