摘要
为研究混凝土桥梁等钢筋混凝土结构在长期重复疲劳荷载耦合外部腐蚀环境下的寿命,首先为加速腐蚀过程,从混凝土小尺寸试件着手,本研究使用真空物理加速方法开展混凝土氯离子腐蚀试验;其次进行混凝土单轴压缩腐蚀疲劳试验。试验结果表明,腐蚀疲劳耦合状态下的混凝土试件呈现出明显贯通主裂缝导致的脆性破坏,应变在加载前期缓慢增加,后期明显加速,裂纹在疲劳寿命75%后在表面开始产生;当腐蚀龄期为6个月时,应力水平为0.6和0.7的试件平均疲劳寿命分别下降了56.5%和96.4%。基于腐蚀疲劳试验的小样本数据集,采用双对数线性方程得到应力比-疲劳寿命方程,混凝土在腐蚀疲劳双因素共同作用下,其影响程度随侵蚀时间的增加而增大,随着腐蚀劣化的加深,相同应力水平下,寿命明显降低,应力水平越大,降低的程度越明显;进一步基于两参数Weibull理论分布概率模型得到疲劳应力水平为0.7和0.6时的寿命概率评估模型,回归方程的相关系数均大于0.990。
The purpose of this study is to research the service life of reinforced concrete structures such as concrete bridges under long-term repeated fatigue load coupled with external corrosion environment.Firstly,this study started with small-sized concrete specimens and conducted chloride ion corrosion tests on concrete using vacuum physical acceleration method to accelerate the corrosion process.Secondly,this study conducted uniaxial compression corrosion fatigue tests on concrete.The test results showed that the concrete specimens in the coupled state of corrosion fatigue exhibited brittle failure caused by obvious through cracks.The strain increased slowly in the early stage of loading and accelerated significantly in the later stage.Cracks began to appear on the surface after 75%of the fatigue life.The average fatigue life of specimens with stress levels of 0.6 and 0.7 decreased by 56.5%and 96.4%when the corrosion age was 6 months,respectively.Then,the stress level fatigue life equation was obtained using a double logarithmic linear equation.Under the combined action of corrosion fatigue factors,the degree of influence of concrete increases with the increase of corrosion time.As corrosion deterioration deepens,the life significantly decreases under the same stress ratio.The larger the stress level,the more obvious the degree of reduction.Thirdly,a two parameter Weibull theoretical distribution model was used to obtain a life probability evaluation model for fatigue stress level of 0.7 and 0.6 based on a small sample dataset of corrosion fatigue tests.The correlation coefficients of the regression equations were all greater than 0.990.
作者
葛海彬
张恒
贾晗曦
刘巍
赵洪光
朱煜英
乔国富
GE Haibin;ZHANG Heng;JIA Hanxi;LIU Wei;ZHAO Hongguang;ZHU Yuying;QIAO Guofu(Mudanjiang Hydroelectric Power Plant,Heilongjiang Electric Power Company Limited,Mudanjiang 157000;Heilongjiang Province Hydraulic Research Institute,Harbin 150080;Harbin Institute of Technology,Harbin 150090)
出处
《中国建材科技》
2025年第4期65-70,共6页
China Building Materials Science & Technology
基金
国家电网公司科技项目(编号:522436240003)
黑龙江省省属科研院所科研业务费项目(编号:CZKYF2024-1-B022)。
