混凝土结构中钢筋锈蚀不均匀性对其力学性能退化的影响  

Effects of Non-uniform Corrosion on Mechanical Degradation of Corroded Rebars in Concrete Structure

作　　者：王晓刚 王宇 秦麟 杜相波[1] WANG Xiao-gang;WANG Yu;QIN Lin;DU Xiang-bo(School of Civil Engineering,Yantai University,Yantai 264005,China)

机构地区：[1]烟台大学土木工程学院,山东烟台264005

出　　处：《烟台大学学报（自然科学与工程版）》2021年第1期69-77,共9页Journal of Yantai University(Natural Science and Engineering Edition)

基　　金：国家自然科学基金资助项目(51108400)。

摘　　要：试验获取锈蚀钢筋试件,借助三维激光扫描建立其实体模型,并进行拉伸试验。通过实体模型精确获取试件残余横截面积分布,建立分段积分模型进行数值拉伸计算并与试验结果对比分析,研究锈蚀不均匀性对锈蚀钢筋力学性能退化的影响。结果发现,沿钢筋长度方向的不均匀性可用区段最大与最小残余横截面积比值μ作为量化参数。随锈蚀发展,不均匀锈蚀系数μ值逐渐增大。然而,剔除锈蚀不均匀性影响后,锈蚀钢筋的屈服强度、极限强度、弹性模量以及极限应变等材性参数没有随锈蚀发展而降低的趋势。基于残余截面积排序的线性简化,以μ为自变量,推导出锈蚀钢筋各个名义材性参数的解析计算公式。显示名义屈服强度、名义极限强度以及名义极限应变均随锈蚀不均匀性增大而显著降低,但严重坑蚀时不能忽略应力集中和周向不均匀锈蚀的不利影响。随锈蚀不均匀性发展,名义弹性模量与强化模量有轻微降低,拉伸曲线的屈服平台逐渐倾斜,并在μ达到约1.1的临界值时融入强化段,宏观屈服平台消失。Corroded rebar specimens are prepared experimentally,and their solid models are built using 3D laser scanning technique before they are finally loaded to failure under tension.The distributions of discrete residual cross-sectional areas of the specimens are acquired precisely from these models,which are used to set up subsection integral models to perform numerical tensile tests.Finally,the effects of non-uniform corrosion on degradation of mechanical properties of corroded bars can be studied through comparing the numerical and experimental results.Shown by the results,the ratio of maximum residual cross-sectional area to the minimum value,denoted asμ,can be used to quantitate the non-uniform corrosion distribution along rebar length.The non-uniform corrosion coefficientμincreases with corrosion aggravation.However,no downward trend can be observed on the rebar mechanical properties,including elastic modulus,yield strength,ultimate strength and ultimate strain,if the influence of non-uniform corrosion has been subtracted.Based on linear simplification of the residual area sequence,analytical formulas are deducted,takingμas attributive variable,for nominal indices of rebar mechanical property.As the developing of the non-uniformity,nominal elastic modulus and hardening modulus both experience slight descending,and yield plateau of the tensile curve inclines gradually until it merges into the hardening branch and disappears phenomenally at a critical state whenμreaches to about 1.1.

关 键 词：混凝土结构 钢筋锈蚀 不均匀性 力学性能 

分 类 号：TU375[建筑科学—结构工程]