天峨龙滩特大桥外包混凝土全过程性能设计与施工质量控制  

Whole Process Performance Design and Construction Quality Control of Encased Concrete of the Tian’e Longtan Bridge

作　　者：陈正[1,2] 陈犇 吴昌杰 郑皆连[1,2] 丁庆军 罗小斌[4] 徐文 杨阳 赵国欣[1,2] CHEN Zheng;CHEN Ben;WU Chang-jie;ZHENG Jie-ian;DING Qing-jun;LUO Xiao-bin;XU Wen;YANG Yang;ZHAO Guo-xin(State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures,Guangxi University,Nanning 530004,Guangxi,China;Key Laboratory of Disaster Prevention and Structural Safety of the Ministry of Education,Guangxi University,Nanning 530004,Guangxi,China;School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,Hubei,China;Guangxi Road and Bridge Engineering Group Co.Ltd.,Nanning 530200,Guangxi,China;State Key Laboratory of High-Performance Civil Engineering Materials,Jiangsu Sobute New Materials Co.Ltd.,Nanjing 21l103,Jiangsu,China)

机构地区：[1]广西大学省部共建特色金属材料与组合结构全寿命安全国家重点实验室,广西南宁530004 [2]广西大学工程防灾与结构安全教育部重点实验室,广西南宁530004 [3]武汉理工大学材料科学与工程学院,湖北武汉430070 [4]广西路桥工程集团有限公司,广西南宁530200 [5]江苏苏博特新材料股份有限公司高性能土木工程材料国家重点实验室,江苏南京211103

出　　处：《中国公路学报》2024年第4期201-211,共11页China Journal of Highway and Transport

基　　金：广西杰出青年科学基金项目(2022GXNSFFA035035);国家自然科学基金重点联合项目(U2006224);国家重点研发计划项目(2021YFB2600903)。

摘　　要：世界最大跨度拱桥天峨龙滩特大桥(在建)跨径长达600 m,要保障其外包混凝土质量,需对其性能与施工质量进行针对性的设计与控制。其难点在于超大跨径条件下混凝土单次泵送方量及距离增加,持续时间增长,以致混凝土工作性能控制难度增大;在浇筑完成后的硬化阶段,需解决降低外包混凝土内外温差、减少局部水化失水干燥、降低收缩应力的问题,以避免裂缝和微缺陷的形成。为解决上述工程难题,揭示了不同原材料和配合比条件下C60外包混凝土力学性能、工作性能及早期体积变化规律,提出了基于早期收缩补偿控制的抗裂混凝土配合比设计方法;根据实际施工流程明确了浇筑区间的工作性能控制指标,建立了基于浇筑区间的工作性能控制方法,全过程中通过外加剂调整技术延长了混凝土最佳施工性能保持时间,提高了施工的效率,有效保障了浇筑均匀性;通过分析计算明确了混凝土入模温度控制要求及方法,揭示了外包混凝土入模及养护施工全过程中的内部温度历程,开展了不同龄期下混凝土在纤维及膨胀剂作用下的混凝土体积变形数值模拟及实测数据对比,从外观及内部体积变形数据上证明了所采用抗裂控制措施合理有效。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

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 

分 类 号：U445.57[建筑科学—桥梁与隧道工程]