高落差自密实混凝土防离析装置试验研究

Research on Anti-segregation Device of Self-compacting Concrete with High Drop

张靖皋长江大桥南航道桥主塔直径3.6 m的钢管混凝土采用大节段浇筑工艺,管内C60自密实混凝土浇筑采用“导管+缓冲装置”。最大浇筑高度为43 m,混凝土易离析,浇筑质量控制难度大。设计了内置式与外置式两种防离析装置,通过对比试验分析了两种不同形式的防离析装置在混凝土浇筑质量上的控制效果,建议在大节段钢管混凝土浇筑工艺中采用3 m布置间距的内置式防离析装置,可大幅减小浇筑过程对混凝土工作性能的不利影响,保证混凝土浇筑质量。

The 3.6 m concrete-filled steel pipe of the main tower of the South Channel Bridge of the Zhang-Jing-gao Yangtze River Bridge adopts the large-segment pouring process,and the C60 selfcompacting concrete pouring in the pipe adopts“conduit+buffer device”.The maximum pouring height is 43 m,thus the concrete is easy to segregate,and control of the pouring quality is difficult.In this paper,two types of built-in and external anti-segregation devices are designed,and the control effect of two different types of anti-segregation devices on the concrete pouring quality is analyzed through comparative tests.It is suggested that the built-in anti-segregation device with 3 m spacing in the large section steel pipe concrete pouring process can greatly reduce the adverse impact of the pouring process on the concrete working performance and ensure the quality of concrete pouring.