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

超薄白面层最初是在北欧和美国开发出来的，用于修复严重车辙的沥青路面，此后这种方法已在世界范围内推广，在日本，该方法已在多个地点进行了试验，并得到了性能数据。收集的性能数据显示，白顶结构至少能够承受中等交通条件5年以上。由于-UFC具有非常致密的基体并含有短纤维，因此与传统混凝土相比，它具有优异的机械性能和耐久性，结合这两种技术，开发了超薄白顶结构高强度混凝土（HSCWT）。在这种方法中，将厚度为 30mm 的 1.0m x 1.7m 面板在工厂中预制，固化条件非常好，放置在现有的沥青路面上。 HSC 板的抗压强度超过 40MPa，远高于普通混凝土板，其通过灌浆将其与沥青层粘合在一起，但对于 HSCWT 的合理结构设计，应充分了解结构的力学性能。 HSC 面板具有非常高的弯曲强度，由于交通荷载而导致面板中的应力预计会非常高，并且取决于下面的沥青层的刚度和厚度。此外，由于沥青层很大。由于比面板厚，沥青层的粘弹性性质不容忽视。本研究为了建立HSCWT的结构设计方法，对HSCWT的全尺寸试验路面和长期性能进行了加速加载试验。进行了 3DFEM 分析来模拟测试并解决 HSCWT 的结构特征，基于载荷测试和 FEM 计算的分析，本研究的结果总结如下。）加速加载试验。HSC-WT 的试验路面是在加速加载设施上建造的，并承受约 150, 000 至 200, 000 次的移动轴荷载。从试验结果可以得出以下结论： ● 未粘结区域。面板之间的接缝，这可能会导致面板支撑力弱并促进非常细小的表面裂纹。 ● 面板底面的石头和硬币纹理类型有效增强了粘合，而孔类型纹理形成了空气空隙● 只要确保面板与沥青层之间的界面处良好的粘合，在交通荷载作用下，HSCWT 的长期性能不会出现严重问题。 ● 与底层面板的接缝加固不存在(2)有限元分析基于动态3DFEM加载试验分析以及计算机结果与实测数据的比较，确定了沥青层的粘弹性参数，研究了HSCWT的机理行为。基于 3DEFM 加载试验的动态分析，可以得出以下结论： ● 对于夏季加载试验，发现沥青层的粘度较低，而对于冬季加载试验，则发现沥青层的粘度相对较高。 ● HSC 面板中的应力。受粘弹性参数和加载速率的影响很小。最显着的影响是面板和灌浆之间的界面条件。 ●如果界面处粘合良好，面板中的应力远小于 HSC 面板的强度。因此，板件的疲劳不会成为HSC-WT结构设计的问题。(3)结构设计方法基于加速加载试验和有限元分析的结果，开发了HSCWT的机械设计程序。在该过程中，使用 3DFEM 计算底层沥青层的拉伸应变，并使用沥青混合料的疲劳曲线根据拉伸应变估计沥青层的疲劳损伤。沥青层和车速对沥青层的疲劳寿命影响较小。