The largest arch bridge in the world,the Tian'e Longtan Bridge(under construction),spans 600 m,and the quality of its encased concrete is safeguarded by designing and controlling its performance and construction quality.The difficulty lies in the fact that the construction of a super-long span simultaneously requires a larger concrete volume and longer pumping distance.Therefore,the pumping duration increases,which makes it more challenging to maintain concrete workability and control concrete uniformity and compactness.In the hardening stage,reducing the temperature difference between the inside and outside of the encased concrete,minimizing the water loss caused by local hydration,and reducing the shrinkage stress are necessary to avoid the formation of cracks and minor defects.To solve these engineering problems,this study explored the mechanical properties,workability,and early volume change of C60-encased concrete with different raw materials and mix proportions,thus proposing a design method for the mix proportion of crack-resistant concrete based on early shrinkage compensation control.According to the actual construction process,the workability control index within a certain casting period was defined,and a workability control method was introduced.Throughout the casting process,the duration for the optimal workability of concrete was extended through admixture adjustment,which increased the construction efficiency and effectively guaranteed concrete uniformity.In addition,through analysis and calculation,the requirements and methods for controlling the concrete casting temperature were determined,and the temperature change of the encased concrete during the entire casting and maintenance process was revealed.Based on this,the numerical simulation of concrete deformation under the action of the fiber and expansion agent and the comparison of measured data were performed at different ages.The appearance and internal deformation prove that the anticracking control measures were reasonable and effective.
关键词
桥梁工程/设计与控制方法/施工控制/外包混凝土/工作性能/体积变形
Key words
bridge engineering/design and control methods/construction control/encased con-crete/workability/volume deformation
维普
万方数据