摘要
针对西部盐渍土环境中地下混凝土结构耐久性及寿命的突出问题,将钢筋混凝土置于NaCl与MgSO4的复合盐溶液中进行耐久性室内加速试验.以腐蚀电流密度作为耐久性退化关键指标,选择Weibull分布函数进行可靠性寿命建模,采用概率分布图进行先验假设检验,通过最小二乘法进行参数估计,利用可靠度曲线、密度曲线及失效率曲线对腐蚀环境中钢筋混凝土进行耐久性预测评估,研究结果表明:Weibull分布模型可有效描述钢筋混凝土在复合盐溶液中的耐久性能退化过程.钢筋混凝土在A、B、C、D复合盐溶液中的耐久性寿命分别3400d、2000d、2900d、1500d.钢筋混凝土在复合盐溶液中的损伤劣化属于耗损型失效.在腐蚀离子综合作用下,钢筋混凝土对NaCl的敏感性高于MgSO_(4),NaCl是影响钢筋混凝土耐久性寿命最主要的因素,复合盐浓度增加10倍,其耐久性寿命缩短至基准溶液寿命的1/2以下.复合盐溶液中,钢筋腐蚀产物是Fe(OH)_(2)、Fe3O4和Fe_(2)O_(3)等的集合体,呈堆积状、颗粒状、层片状,复合盐溶液浓度越高,钢筋腐蚀产物越致密.
Aiming at the prominent problems of durability and service life of underground concrete structures in western saline soil environment in China,the reinforced concrete was placed in NaCl and MgSO_(4)compound salt solution for the durability indoor acceleration test.Corrosion current density was used as the key degradation index of durability.Weibull distribution function was selected for reliability life modeling,the prior hypothesis test was conducted by using the probability distribution diagram.Parameters were estimated by least square method.The reliability curve,density curve and failure rate curve were utilized to predict and evaluate the durability life of reinforced concrete in corrosive environment.The results show that:Weibull distribution model can effectively describe the durability degradation process of reinforced concrete in composite salt solution.The durability life of reinforced concrete in A,B,C and D compound salt solution is 3400 days,2000 days,2900 days and 1500 days respectively.The damage and degradation of reinforced concrete in the compound salt solution belong to the loss type failure.Under the comprehensive action of corrosion ions,the sensitivity of reinforced concrete to NaCl is higher than that of MgSO_(4),a nd NaCl is the most important factor affecting the durability and life of reinforced concrete.When the concentration of compound salt increases by 10 times,the durability life reduce to less than 1/2 of the reference solution life.The corrosion products of steel bar are the aggregation of Fe(OH)_(2),Fe_(3)O_(4)and Fe_(2)O_(3),and the morphology of the corrosion products is accumulation,granule and lamellar.The higher the concentration of compound salt solution,the more dense the corrosion products are.
作者
路承功
魏智强
乔宏霞
乔国斌
付勇
LU Chenggong;WEI Zhiqiang;QIAO Hongxia;QIAO Guobin;FU Yong(School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China;School of Science,Lanzhou University of Technology,Lanzhou 730050,China;Western Center of Disaster Mitigation in Civil Engineering of Ministry of Education,Lanzhou University of Technology,Lanzhou 730050,China)
出处
《应用基础与工程科学学报》
EI
CSCD
北大核心
2022年第6期1534-1544,共11页
Journal of Basic Science and Engineering
基金
国家自然科学基金项目(51168031,51868044)
