桥梁结构修补中UHPC-NC黏结界面的收缩性能  

Shrinkage Performance of UHPC⁃NC Bonding Interface in Bridge Structure Repair

作　　者：刘玉静 夏浩 刘国梁 朱尧于 郭佳傲 LIU Yujing;XIA Hao;LIU Guoliang;ZHU Yaoyu;GUO Jiaao(Jiangsu Expressway Engineering Maintenance Co.Ltd.,Nanjing 211106,China;Jiangsu Sutong Bridge Co.Ltd.,Nantong Jiangsu 226007,China;School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China;CCCC Highway Bridges National Engineering Research Center Co.Ltd.,100088,China)

机构地区：[1]江苏高速公路工程养护技术有限公司,南京211106 [2]江苏苏通大桥有限责任公司,江苏南通226007 [3]北京交通大学土木建筑工程学院,北京100044 [4]中交公路长大桥建设国家工程研究中心有限公司,北京100088

出　　处：《铁道建筑》2024年第9期140-146,共7页Railway Engineering

基　　金：中国交通建设集团有限公司科技研发项目(YSZX-03-2021-01-B)。

摘　　要：将超高性能混凝土(Ultra-high Performance Concrete,UHPC)应用于桥梁构件修补时,为明确后浇UHPC和既有普通混凝土(Normal Concrete,NC)黏结界面的收缩变形及应力分布,通过开展UHPC-NC黏结试件的收缩试验,测量了UHPC试件的自由收缩变形和UHPC-NC黏结试件的约束收缩变形;建立有限元分析模型,讨论了黏结界面的滑移,分析了界面和后浇UHPC中的应力分布及影响因素。结果表明:UHPC的自由收缩应变增长符合指数发展规律;UHPC-NC黏结试件的界面存在滑移,滑移可有效降低界面应力;界面开裂应力随修补层厚度的减小而增加,随着修补底面面积的增大而增加;黏结界面端部受到收缩引起的切应力最大;界面应力随黏结龄期增长而呈现出先快速增加后逐渐趋于稳定的特征,UHPC中的钢纤维可以降低界面应力。UHPC用作混凝土修补时不会出现因收缩受约束而开裂的问题,是理想的桥梁构件修补材料。When applying ultra-high performance concrete(UHPC)to repair bridge components,in order to clarify the shrinkage deformation and stress distribution of the bonding interface between post poured UHPC and existing normal concrete(NC),shrinkage tests were conducted on UHPC-NC bonded specimens to measure the free shrinkage deformation of UHPC specimens and the constrained shrinkage deformation of UHPC-NC bonded specimens.A finite element analysis model was established to discuss the slip of the bonding interface,and the stress distribution and influencing factors in the interface and post poured UHPC were analyzed.The results indicate that the free shrinkage strain growth of UHPC follows an exponential development law.The interface of UHPC-NC bonded specimens exhibits slip,which can effectively reduce interfacial stress.The interface cracking stress increases with the decrease of repair layer thickness and the increase of repair bottom surface area.The maximum shear stress is caused by shrinkage at the end of the bonding interface.The interface stress shows a rapid increase followed by a gradual stabilization as the bonding age increases,and steel fibers in UHPC can reduce the interface stress.UHPC is an ideal bridge component repair material as it does not experience cracking due to shrinkage constraints when it is used for concrete repair.

关 键 词：超高性能混凝土 桥梁 修补材料 UHPC-NC黏结试件 收缩 界面应力 

分 类 号：U445.7[建筑科学—桥梁与隧道工程]