钢管拱内混凝土超长距离泵送性能

Ultralong Distance Pumpability of Core Concrete Filled in Steel Tube Arch

采用一种适用于大流动性混凝土的新型"摩擦计",模拟测试了藏木大桥钢管拱内C60高强自密实混凝土沿泵管壁形成的润滑层屈服应力和黏度常数,分别约48 Pa和723 Pa·s·m^–1,据此计算得到混凝土泵送阻力。设计了混凝土超长距离泵送试验钢管拱节段选取及泵管设置方案,分别测试了混凝土在泵管和钢管拱内的泵送阻力。结果表明:约30 m^3/h排量下,采用基于滑流模式的Morinaga公式的泵管内混凝土泵送阻力计算值与实测值分别约19.8kPa/m和20.6kPa/m,误差不超过5%,钢管拱内则只有5.4 kPa/m,约为泵管内值的28%。

A tribometer suitable for highly-workable concrete was used to examine the yield stress and viscous constant of lubrication layer along a smooth pump pipe wall formed by C60 high-strength self-consolidating concrete filled in the steel tube arch of Zangmu Bridge. The yield stress and viscous constant are 48 Pa and 723 Pa·s·m^–1, respectively, based on the calculated pumping resistance. Also, an experimental plan of steel tube arch test section selection and pump pipe arrangement for concrete ultralong distance pumpability characterization was designed. The pumping resistance both in pump pipe and steel tube arch was examined, respectively. The results indicate that the values of concrete pumping resistance in pump pipe calculated by the Morinaga formula based on a slip flow model and measured in the ultralong distance pumping experiment are 19.8 kPa/m and 20.6 kPa/m, respectively, under 30 m^3/h pump displacement. Besides, the concrete pumping resistance in steel tube arch is only 5.4 kPa/m, which is approximately 28% of that in pump pipe.