混凝土中氯离子扩散数值分析方法及实桥应用  

Numerical simulation method of the chloride ion diffusion in concrete and its application in bridge

作　　者：胡守旺[1] 彭建新[1] 张建仁[1] HU Shouwang;PENG Jianxin;ZHANG Jianren(Key Lab of Safety Control of Bridge Engineering Established by Department of Education and Hunan Province,Changsha University of Science & Technology, Changsha 410004, China)

机构地区：[1]长沙理工大学桥梁结构安全控制教育部重点实验室,湖南长沙410114

出　　处：《铁道科学与工程学报》2017年第12期2570-2579,共10页Journal of Railway Science and Engineering

基　　金：国家重点基础研究发展计划(973计划)项目[2015CB057701];国家自然科学基金面上资助项目[51178060];交通运输部主干学科应用基础研究资助项目[2014319825160];湖南省教育厅优秀青年资助项目[15B015];桥梁结构安全控制湖南省工程实验室开放基金资助项目[14KD12];湖南省研究生创新省级资助项目[CX2015B344];桥梁结构安全控制和耐久性评估的理论研究及工程应用团队建设资助项目[15YTD07]

摘　　要：氯离子在混凝土中扩散聚积到一定浓度后会引起钢筋锈蚀,钢筋锈蚀引起的混凝土保护层锈胀开裂影响钢筋混凝土结构正常使用性能,对氯离子扩散系数进行修正,修正系数可以考虑时间效应、温度效应和湿度效应,将修正扩散系数与有限元软件结合得到氯离子渗透数值分析方法,通过氯离子在试块中一维和二维渗透试验结果对数值分析方法进行验证,最后将数值分析方法应用到实桥中。研究结果表明:基于本文建立的氯离子渗透数值分析方法的计算值与试验值吻合较好;预应力T梁在考虑氯离子空间分布下,相同深度而位置不同处的氯离子浓度不同,最外层钢筋在100 a时氯离子浓度最大值为0.231%;预应力箱梁计算结果说明底板角部钢筋在最大龄期100 a时氯离子浓度为1.03 kg/m3是中部位置氯离子浓度的1.30倍,结果均小于临界氯离子浓度,说明箱梁内钢筋在服役期内不会发生锈蚀。Chloride-induced corrosion can influence the serviceable performance of RC structures.A numerical analysis method was proposed on the basis of the modified diffusion model and finite element software in chlorides to verify the multi-dimensional diffusion test results.The chloride ion concentration prediction was then conducted in two engineering projects.Research results show that:the values calculated by the numerical model are in good agreement with the test values.When the spatial distribution of chloride concentration is taken into account,the chloride concentration is different at the same depth but different position of prestressed T-beam.The maximum chloride concentration of the outermost layer of reinforcing bar is0.231%at time of100a.The chloride concentration at the corner of bottom slab with depth of40mm to exposed area is1.03kg/m3which is1.30times of that at middle of bottom slab for prestressed concrete box girder at time of100a.The maximum chloride concentration is less than the critical chloride concentration that corrosion of the reinforced bars in concrete will not happen.

关 键 词：桥梁工程 混凝土 氯离子 修正扩散系数 数值分析 

分 类 号：U444[建筑科学—桥梁与隧道工程]