摘要
混凝土病害性膨胀下构件内部箍筋角部的脆断被认为与钢筋弯折过程中的初期损伤有关,值得深入研究。本工作针对常用带肋钢筋,通过加工参量下的90°弯折试验发现,钢筋横肋根部出现最大长度约占直径2.52%的初期裂纹。弯折钢筋的拉伸试验表明,因初期裂纹扩展,试件均在极限拉伸前形成早期断裂,且断裂强度最低仅为极限拉伸强度的60%。由断口分析得出,弯折钢筋最小断面收缩率仅为正常直钢筋的34%,且断口呈典型的脆性特征。长期服役会进一步加剧箍筋角部强度及塑性变形性能的劣化。本研究将为进一步优化弯折钢筋的工程应用和力学性能设计提供参考。
The brittle fracture of stirrup inside the structural member under the action of concrete disease expansion is considered to be related to the incipient damage formed during the bending process of the reinforcing bars,and it is worthy of in-depth study.Commonly used ribbed bars are utilized to carry out 90°bending tests under various processing parameters.It was found that the incipient cracks occurred with the maximum length accounting for 2.52%of the reinforcing bar diameter.Through the tensile test of the bent reinforcing bar,it can be learned that all specimens experienced an early fracture due to the progress of the incipient crack,with the minimum fracture strength as only 60%of the ultimate tensile strength.According to the analysis of the fracture surface,the minimum section shrinkage rate of the bent reinforcing bar was only 34%of the normal straight reinforcing bar,and the fracture surface showed a typical brittle characteristic.The long-term service can further aggravate the deteriorations of strength and plastic deformation property in the corner stirrup.This research will provide a reference for further optimizing the engineering application and mechanical properties design of bent steel bars.
作者
郑玉龙
刘翔
陆春华
步森壮
幸左贤二
ZHENG Yulong;LIU Xiang;LU Chunhua;BU Senzhuang;KOSA Kenji(Faculty of Civil Engineering and Mechanics,Jiangsu University,Zhenjiang 212013,Jiangsu,China;Department of Civil and Architectural Engineering,Kyushu Institute of Technology,Kitakyushu 8038501,Japan)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2022年第23期117-122,共6页
Materials Reports
基金
国家自然科学基金(52108147,51878319)
江苏省博士后科研资助计划(2020Z350)
江苏大学高级人才基金(20JDG19)。
关键词
混凝土耐久性
钢筋脆断
初期损伤
时效作用
力学性能
concrete durability
brittle fracture of stirrup
incipient damage
aging effect
mechanical property
