[Commentary] On the evening of April 17, after 13 consecutive hours of construction work, the concrete pouring into the first main chord pipe of the third Pingnan Bridge in Guangxi was completed successfully.
【Explanation】 The third Pingnan Bridge is located in Pingnan, Guangxi. It is a special bridge that crosses the Xunjiang River on the Pingnan-North Interconnecting Line of the Liyu Expressway. After completion, it will be the world's largest span arch bridge.
[Explanation] C70 self-compacting non-shrinkage concrete (hereinafter referred to as C70 concrete) is used for concrete pouring in the first pipe of Pingnan No.3 Bridge, which is vacuum-assisted four-stage continuous pumping for pipe pouring. Its outstanding advantage is that by adding classification and sub-bin , A number of exhaust pipes, sizing tanks and other methods are provided to greatly improve the compactness of concrete pouring in the pipes and reduce the risks of pipe plugging and bubble accumulation.
【Explanation】 In order to ensure the optimal performance of C70 concrete, the research and test team of the Guangxi Luqiao Group project jointly exerted force, and repeatedly learned from industry experts such as Zheng Jielian, academician of the Chinese Academy of Engineering, and Ding Qingjun, professor of Wuhan University of Technology, and finally broke through material selection and cooperation. Difficulties such as optimization, successfully prepared C70 concrete with excellent working performance, controllable compensation shrinkage process, and mechanical properties that meet the design requirements. In order to ensure the high efficiency and quality of the infusion cycle, the project department intervened in advance to deploy and strictly control the materials. At present, the arrival rate of Pingnan Third Bridge materials and equipment has reached 100%, and the first quality control has been accurately controlled from the source.
[Same period] Zheng Jielian, academician of the Chinese Academy of Engineering
Its main breakthrough is that there is more than 900 cubic meters of concrete in a tube in this tube. If it is to be poured in an initial setting time in a continuous operation, then more than 900 cubic meters of concrete will cause it to have problems on either side. Causes irreparable defects, so to ensure that more than 900 square meters (concrete) of more than 10 hours of construction, each plate, each car concrete is good, the management is still very difficult, this material requirements are harsh At this point, the requirements for the process have reached a harsh level.
[Explanation] It is reported that there are a total of 8 main arch ribs of the Pingnan Third Bridge, which are infused by vacuum-assisted four-stage continuous pumping process, which requires a total of 8 infusions. This time, the main string is 650m long and 1.4m in diameter. It needs about 1000m of concrete to be poured. The continuous pouring time is about 13 hours. After the coagulation strength in the pipe reaches 80%, the next main string can be continued. Concrete pouring construction, the concrete pouring construction in the full bridge pipe is expected to take about 30 days.
Ma Boyu Liang Yangshan Guangxi Guigang Report
Responsible editor: [Luo Pan]