液化氮在降低混凝土出仓温度中的应用

以新建云桂铁路南盘江特大桥拱座基础大体积混凝土施工为依托,为保证在夏季高温季节施工中混凝土入模温度符合规范不大于30℃的规定,研发了采用液化氮降低混凝土出仓温度的方法,在拌合机搅拌罐内安装液化氮供应管道,并将液化氮供应管道与现场的小型液氮供气站相连,在混凝土拌合过程中利用自增压液氮气罐连续向拌合机搅拌罐内注入低温氮气,在混凝土搅拌过程中对混凝土进行充分的降温,可以根据需要调节液化氮的供气量和混凝土拌合时间来调整降温的幅度。有效降低了混凝土的出仓温度,保证了混凝土的施工质量。

On the Application of Liquefied Nitrogen to Lowering the Temperature of Concrete in Storehouses

With the construction of the mass concrete of the arch abutment foundation of the Nanpanjiang Mega Bridge of the newly-built Yun-Gui Railway as a practical example,the method of using liquefied nitrogen to reduce concrete temperature in the storehouse is developed in this paper,in order to satisfy the requirement in the temperature of concrete when it is cast,which should be limited to no more than 30℃during the construction in summer when it is very hot.Inside the mixing tank,provided is a liquefied nitrogen supply pipeline,which is connected with a small liquefied nitrogen supply station at the construction site.During the stirring operation,the cryogenic nitrogen gas will be continuously injected into the mixing tank by a self-pressurized liquefied nitrogen tank,which can reduce concrete temperature in the mixing process.The cooling range can be adjusted according to the liquefied nitrogen supply and the time of concrete mixing.The method may effectively help lower the temperature of concrete and ensure the construction quality of the concrete.