摘要
为研究镁水泥钢筋再生细骨料混凝土在盐渍土环境中的服役寿命,通过控制再生细骨料的掺量制备镁水泥钢筋再生细骨料混凝土试件并暴露于西宁盐渍土地区,定期进行超声声速、电阻无损检测,结合SEM微观测试手段对试件内部结构损伤程度进行对比分析,基于维纳随机分布函数建立寿命模型.结果表明,存在有害离子和恶劣气候环境双重因素作用下,试件的动弹模量评价参数λ1先增后降,钢筋锈蚀评价参数λ2始终呈下降趋势;当分别掺入15%、30%和45%的细骨料时,Cl^(-)、CO^(2-)_(3)和SO_(4)^(2-)等侵蚀性离子随着再生细骨料掺量的增加侵入试件内部几率增大,与镁水泥水化产物反应生成的膨胀性晶体越多,导致基体内部结构损伤程度更加显著;λ1和λ2作为耐久性退化参数可以准确得到试件的可靠度函数,以λ1作为退化参数得到不同掺量试件的服役寿命分别为22 000d、20 000d、16 000d,以钢筋电阻值得到的服役寿命分别为16 000d、15 000d、12 000d,钢筋电阻耐久性变化更敏感,可用于钢筋混凝土构件的日常维护与检测.
In order to study the service life of magnesium cement reinforced recycled fine aggregate concrete in saline soil environment,magnesium cement reinforced recycled fine aggregate concrete specimens were prepared by controlling the content of recycled fine aggregate and exposed to Xining saline soil area.Resistance nondestructive testing,combined with SEM microscopic testing methods to compare and analyze the damage degree of the internal structure of the specimen,and established a life model based on the Wiener random distribution function.The results show that under the influence of both harmful ions and harsh climate environment,the dynamic elastic modulus evaluation parameterλ1 of the specimen increases first and then decreases,and the steel corrosion evaluation parameterλ2 always shows a downward trend;When adding 15%,30%and 45%of fine aggregate,the erosive ions such as Cl^(-),CO^(2-)_(3) and SO_(4)^(2-) have an increased probability of invading the interior of the specimen with the increase of the content of regenerated fine aggregate.react with magnesium cement hydration products to form expansive crystals.λ1 andλ2 can be used as the durability degradation parameters to accurately obtain the reliability function of the specimen.λ1 is used as degradation parameter,the working lives of the specimens with different dosages are 22000d,20000d and 16000d,respectively,the service life obtained by the steel resistance value is 16000d,15000d and 12000d respectively.The steel resistance durability is more sensitive,which can be used for daily maintenance and detection of reinforced concrete members.
作者
杨天霞
乔宏霞
温少勇
王鹏辉
李金鹏
YANG Tianxia;QIAO Hongxia;WEN Shaoyong;WANG Penghui;LI Jinpeng(Key Laboratory of Earthquake Prevention and Disaster Reduction of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China;Qinghai Salt Lake Research Institute,Chinese Academy of Sciences,Xining 810008,China;Qinghai Minzu University,Xining 810007,China)
出处
《应用基础与工程科学学报》
EI
CSCD
北大核心
2023年第4期977-989,共13页
Journal of Basic Science and Engineering
基金
国家自然科学基金项目(51868044)
面上项目(52178216)
青海省基础研究计划项目(2022-ZJ-921)。
关键词
镁水泥钢筋再生细骨料混凝土
寿命预测模型
可靠度函数
钢筋电阻
动弹性模量
magnesium cement reinforced recycled fine aggregate concrete
life prediction model
reliability function
steel resistance
dynamic elastic modulus
