重轴载交通下斜向预应力混凝土路面应用研究

针对重轴载交通下普通水泥混凝土路面抗疲劳性能较差、容易产生裂纹的问题,提出将斜向预应力混凝土路面引入重轴载交通中,并结合已有定测下混凝土疲劳试验结果对其抗疲劳机理进行深入分析.同时,根据混凝土疲劳破坏发展的历程,提出此种路面结构中预应力筋的分步张拉方法:当混凝土浇筑完成24h后,预应力筋第一次张拉到30%的设计轴力,以控制混凝土路面初期裂纹;当混凝土达到设计龄期后,张拉至设计轴力用以抵消温度应力和部分重轴载引起的路面拉应力,保证路面结构在正常使用情况下处于三维压缩状态,从而防止混凝土裂纹的出现和扩展,达到提高混凝土第二阶段抗疲劳强度的目的.实例验证了斜向预应力混凝土路面结构适用于重轴载交通.

Research on application of cross tensioned concrete pavements to heavy axle loading traffic

To improve the poor anti-fatigue performance and easily cracking characteristics of plain cement concrete pavements, cross tensioned concrete pavements (CTCP) were proposed to suit the heavy axle loading traffic conditions, and their anti-fatigue mechanism was deeply analyzed combining with existing concrete fatigue location survey data.Furthermore, the step-by-step tensioning method of prestressed reinforcement was put forward according to the development process of concrete fatigue damage. Firstly, 24 h later after finishing concrete pouring,the prestressed reinforcement was tensioned to 30% of design axis force, which could decrease concrete initial cracks effectively.Then, while reaching the design age of concrete,the prestressed reinforcement was tensioned to the full design axis force, which could counteract the temperature load and part pavements tensile stress caused by heavy axle load, ensuring the concrete pavements in 3D compression state under normal working situation. Thus, the objective of increasing concrete anti-fatigue performance in the second stage was reached through preventing concrete cracks from arising and extending. Finally, a practical instance testifies that the CTCP are appropriate for heavy axle loading traffic.