浇筑体积对拱座水化热影响的研究

Study on the Influence of Pouring Volume on Hydration Heat of Skewback

大跨径上承式钢管混凝土拱桥的钢筋混凝土拱座具有结构复杂、体积庞大等特点,在浇筑拱座的过程中易出现因混凝土水化热控制不当引起的温度裂缝,倘若出现贯穿裂缝将会对拱座的结构造成严重破坏。为解决温度裂缝影响拱座使用过程中的耐久度和最终的承载力的问题,以正在修建中的重庆某大跨径上承式钢管混凝土拱桥为项目背景,选取北岸拱座的前4个单元为分析对象,采用布设温度传感器的方法对拱座水化热进行测量监控和数据分析,研究不同浇筑体积下混凝土水化热变化的差异与规律,得出了有关大体积混凝土水化热峰值温度、温度增加速率、浇筑工艺对升降温的影响等一系列结论,总结其特点与规律,以便对往后的大体积混凝土水化热控制起到指导和参考的作用。

Reinforced concrete skewback of large-span top-supported concrete-filled steel tube arch bridge has the characteristics of complex structure and huge volume,and it is easy to appear temperature cracks caused by improper hydration heat control of concrete in the process of pouring the skewback.If there are through cracks,the structure of the skewback will be seriously damaged.In order to solve the problem that the temperature cracks affect the durability and ultimate bearing capacity of the skewback during its use,taking a long-span top-supported concrete-filled steel tube arch bridge in Chongqing as the project background,this paper selected the first four units of the north bank skewback as the analysis object,using the method of setting temperature sensors to perform measurement monitoring and data analysis for skewback hydration heat.The differences and rules of hydration heat variation of concrete under different pouring volumes were studied.A series of conclusions is drawn about the peak temperature of hydration heat of mass concrete,the temperature increase rate and the influence of pouring technology on the temperature rise and decrease.Its characteristics and rules are summarized to play a guiding and reference role in the future control of hydration heat of mass concrete.