常泰长江大桥主航道桥主墩承台大体积混凝土抗裂技术研究  

Research on Cracking Control Techniques for Large-Volume ConcretePile Caps Supporting Pylon Piers of Main Navigational ChannelBridge of Changtai Changjiang River Bridge

作　　者：潘利 徐文 梁志雯 王育江 PAN Li;XU Wen;LIANG Zhiwen;WANG Yujiang(State Key Laboratory of High Performance Civil Engineering Materials,Nanjing 211103,China;Jiangsu Sobute New Materials Co.,Ltd.,Nanjing 211103,China;Jiangsu Transportation Engineering Construction Bureau,Nanjing 210004,China)

机构地区：[1]高性能土木工程材料国家重点实验室,江苏南京211103 [2]江苏苏博特新材料股份有限公司,江苏南京211103 [3]江苏省交通工程建设局,江苏南京210004

出　　处：《桥梁建设》2024年第3期8-14,共7页Bridge Construction

基　　金：国家自然科学基金项目(52378239,52178214)~~。

摘　　要：常泰长江大桥主航道桥为主跨1 208 m的公铁两用双塔钢桁梁斜拉桥,主墩承台尺寸为77 m(横桥向)×39.8 m(顺桥向)×8 m(厚),采用C40混凝土,单个承台混凝土超过2万方。为降低承台大体积混凝土开裂风险,提高其抗裂性能,采用具有水化热调控和补偿收缩的功能性材料,基于温度场和变形场协同调控试验,开展承台大体积混凝土抗裂技术研究。试验结果表明:水化热调控材料可有效降低水泥水化热及放热速率,调控混凝土温度历程,有利于减少大体积混凝土温度裂缝;复合膨胀材料可以调控混凝土变形历程,有利于减小混凝土收缩变形,抑制混凝土收缩开裂。根据研究结果,该桥主墩承台混凝土掺加0.2%的水化热调控材料和8%的复合膨胀材料(配比为50%CaO+50%MgO),施工过程中采取控制入模温度、设置冷却水管、加强保温与保湿养护等措施。主墩承台混凝土拆模后未见裂缝,说明基于温度场和变形场协同调控的混凝土抗裂技术应用效果较好。With a main span of 1208 m,the main navigational channel bridge of Changtai Changjiang River Bridge is a two-pylon steel truss girder cable-stayed bridge accommodating both road and rail traffic.The pile caps supporting pylon piers measure 77 m by 39.8 m,8 m in height,and each pile cap consumes 20000 m 3 of C40 concrete.The materials capable of hydration heat regulation and shrinkage compensation were used to alleviate the cracking risk and improve anti-cracking performance of large-volume concrete pile caps.Based on the coordinated regulation of the temperature and deformation fields,the cracking resistant techniques for large-volume concrete pile cap were studied.It is shown that the hydration heat regulating materials can effectively reduce the hydration heat and heat release rate of cement,regulate temperature history of concrete,thereby alleviating the thermal cracking of large-volume concrete pile cap.Composite expansion materials can regulate the deformation history of concrete and effectively reduce the shrinkage deformation and cracking of concrete.The concrete of pile cap was mixed with 0.2%hydration heat regulating material and 8%composite expansion material(50%CaO and 50%MgO).During construction,multiple measures were taken,including controlling the concrete pouring temperature,placing cooling water pipes,and maintaining proper thermal and moisture conditions during concrete curing.No cracks were observed in the demolded concrete pile cap,indicating that the temperature and deformation field coordinated concrete control techniques were effective.

关 键 词：斜拉桥 承台大体积混凝土 水化热调控材料 复合膨胀材料 温度场 变形场 协同调控 混凝土抗裂技术 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] U443.25[交通运输工程—道路与铁道工程] U445.57