静载与钢筋锈蚀共同作用对再生混凝土梁受弯性能影响  

Influence of combined effects of static load and steel corrosion on flexural performance of recycled concrete beams

作　　者：王健 严蕤 苏瀚 杜进生 李雅娟[2] 牛宏[2] WANG Jian;YAN Rui;SU Han;DU Jinsheng;LI Yajuan;NIU Hong(School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China;CCCC First Highway Consultants Co.,Ltd.,Xi’an 710075,China)

机构地区：[1]北京交通大学土木建筑工程学院,北京100044 [2]中交第一公路勘察设计研究院有限公司,陕西西安710075

出　　处：《建筑结构学报》2020年第S01期238-246,共9页Journal of Building Structures

基　　金：宁波市科技局重大专项项目(2015C110020);陕西省交通厅交通科技项目(10-43K);甘肃省交通运输厅科技项目(201607);江苏省交通工程建设局科技项目(C18L01160)

摘　　要：为研究静载与钢筋锈蚀共同作用下再生混凝土梁的受弯性能,考虑3种再生粗骨料取代率(0、50%、100%)及4种静载水平(0、0.2Mu1、0.4Mu1、0.6Mu1,Mu1为对比梁的受弯承载力)的组合,共设计了9根再生混凝土梁进行加速锈蚀试验与静力加载试验。试验结果表明:当再生粗骨料取代率由0%增加到100%时,纵向受拉钢筋最大质量损失率与平均质量损失率分别增大了12.1%和9.5%;对于再生粗骨料取代率为50%的锈蚀梁,当静载水平由0增加到0.6Mu1时,纵向受拉钢筋最大质量损失率与平均质量损失率分别增大了43.5%和60.6%,加载破坏时梁受拉裂缝数量减少了21.4%,梁底面受拉裂缝平均间距增大了29.8%,梁屈服荷载与极限荷载分别降低了13.8%和10.4%,屈服挠度与极限挠度分别降低了17.0%和21.2%;当纵向受拉钢筋质量损失率低于7%时,其与周围再生混凝土之间能保持有效黏结,锈蚀再生混凝土梁加载时发生弯曲破坏;锈蚀再生混凝土梁的承载力随再生粗骨料取代率的增加而降低,而跨中挠度随再生粗骨料取代率的增加而增大,但总体上变化幅度不大;正常使用荷载范围内,平截面假定适用于未锈蚀与锈蚀再生混凝土梁。In order to investigate the influence of combined effects of static load and steel corrosion on the flexural performance of recycled concrete beams,considering three types of recycled coarse aggregate( RCA) replacement ratios( i. e.,0,50%,and 100%) and four levels of static loads( i. e.,0,0. 2 Mu1,0. 4 Mu1,and 0. 6 Mu1,Mu1 is the flexural capacity of the contrast beam),nine recycled concrete beams were designed for accelerated corrosion test and static loading test. The results show that when the RCA replacement ratio increases from 0% to 100%,the maximum and average mass loss rate of longitudinal tensile reinforcement increase by 12. 1% and 9. 5%,respectively. For the corroded beams with RCA replacement ratio of 50%,when the applied static load level increases from 0 to 0. 6 Mu1,the maximum and average mass loss rate of longitudinal tensile reinforcement increase by 43. 5% and 60. 6%,respectively,the number of tensile cracks is reduced by 21. 4% when the corroded beams are damaged by loading,the average spacing of tensile cracks on the bottom of corroded beams increases by 29. 8%,the yield load and ultimate load of corroded beams are reduced by 13. 8% and 10. 4%,respectively,and the yield deflection and ultimate deflection decrease by 17. 0% and 21. 2%,respectively. When the mass loss rate of longitudinal tensile steel bars is lower than 7%,the bond between the corroded steel bars and the surrounding recycled aggregate concrete( RAC) can be effectively maintained,and the corroded beams are flexural failure in four-point bending test. The bearing capacity of corroded beams decreases with the increase of the RCA replacement ratio,while the mid-span deflection increases with the increase of the RCA replacement ratio,but on the whole,the change range is not large. Within the normal service load range,the plane-section assumption is applicable to the uncorroded and corroded recycled concrete beams.

关 键 词：再生混凝土梁 静载 钢筋锈蚀 裂缝 受弯性能 

分 类 号：TU375.1[建筑科学—结构工程]