通电加速与氯盐干湿条件下钢筋锈蚀的时间相似关系试验
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摘要
为了研究氯盐侵蚀环境下混凝土内钢筋的锈蚀发展规律,以环境-时间相似理论模型为指导,开展恒电流通电加速试验与自然环境氯盐干湿循环试验,利用法拉第定律计算钢筋锈蚀率,以两种侵蚀条件下的钢筋锈蚀率接近为条件建立两者间的时间相似关系模型。试验结果表明:以自然氯盐侵蚀环境下钢筋锈蚀率实测值为4. 04%的试件为例,达到相同锈蚀率,恒电流通电加速锈蚀试验所需时间为160 h,由时间相似关系模型计算得到两种侵蚀环境条件下的时间相似系数为0. 025,从而求得自然氯盐环境条件下的钢筋锈蚀时间预测值为4. 0 a,与试验值3. 836 a间的误差为4. 28%,验证了本文所建立的基于钢筋锈蚀率的时间相似模型的可行性,为预测氯盐环境下混凝土结构钢筋锈蚀提供一定的理论参考。
In order to explore the degradation process of steel in concrete structure under the coupling of chloride and loads,based on the environment-time similarity model,the constant electric current acceleration test and natural aggressive test were carried out.The corrosion rate of steel bar was calculated by Faraday rust law.The corrosion rates of steel bars in two chloride environments with coupling load were approached.Based on the corrosion rate of reinforcing bars,the time similarity model of reinforcement rust was established. Results revealed that when the corrosion rate of the component in the two chloride environments with coupling load was 4. 04%,the time needed in constant current charging acceleration test was 160 h. The time similarity model coefficient calculated was 0. 025. Based on the modeling findings,the predicted corrosion time of the natural environment test component was 4 a with the error between the theoretical and experimental value( 3. 836 a) of 4. 28%.Therefore,the similarity model could provide a theoretical method for predicting the corrosion rate of steel bars in concrete structures under natural environments.
In order to explore the degradation process of steel in concrete structure under the coupling of chloride and loads,based on the environment-time similarity model,the constant electric current acceleration test and natural aggressive test were carried out.The corrosion rate of steel bar was calculated by Faraday rust law.The corrosion rates of steel bars in two chloride environments with coupling load were approached.Based on the corrosion rate of reinforcing bars,the time similarity model of reinforcement rust was established. Results revealed that when the corrosion rate of the component in the two chloride environments with coupling load was 4. 04%,the time needed in constant current charging acceleration test was 160 h. The time similarity model coefficient calculated was 0. 025. Based on the modeling findings,the predicted corrosion time of the natural environment test component was 4 a with the error between the theoretical and experimental value( 3. 836 a) of 4. 28%.Therefore,the similarity model could provide a theoretical method for predicting the corrosion rate of steel bars in concrete structures under natural environments.
引文
[1]金伟良,赵羽习.混凝土结构耐久性[M].2版.北京:科学出版社,2014.
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[9]宋华,牛荻涛.电化学快速锈蚀与自然环境钢筋锈蚀的相似性分析[J].西安建筑科技大学学报(自然科学版),2009,41(4):508.
[10]JIN W L,LI Z Y,CHEN J,et al.Dynamic life prediction of RCstructures on multi-environmental time similarity method[J].Advanced Materials Research,2011,255/260:220.
[11]OTIENO M,BEUSHAUSEN H,ALEXANDER M.Chlorideinduced corrosion of steel in cracked concrete-part I:experimental studies under accelerated and natural marine environments[J].Cement and Concrete Research,2016,79:373.
[12]WANG X G,SONG X W,ZHANG M P,et al.Experimental comparison of corrosion unevenness and expansive cracking between accelerated corrosion methods used in laboratory research[J].Construction and Building Materials,2017,153:36.
[13]储炜,史苑芗,魏宝明.钢筋在混凝土模拟孔溶液及水泥净浆中的腐蚀电化学行为[J].南京化工学院学报,1995,17(3):14
[14]VU K T,STEWART M G.Predicting the likelihood and extent of reinforced concrete corrosion-induced cracking[J].Journal of Structural Engineering,2005,131(11):1681.
[15]VU K T,STEWART M G.Structural reliability of concrete bridges including improved chloride-induced corrosion models[J].Structural Safety,2000,22(4):313.
[2]刘荣桂,曹大富,陆春华.现代预应力混凝土结构耐久性[M].北京:科学出版社,2013.
[3]GHODS A,SOHRABI M R,MIRI M.Effect of rebar corrosion on the behavior of a reinforced concrete beam using modeling and experimental results[J].Materiali in Tehnologije,2014,48(3):395.
[4]GJ?RV O E.Durability design of concrete structures in severe environments(Second edition)[M].New York:Taylor&Francis Group,CRC Press,2014.
[5]陆春华,赵羽习,金伟良.锈蚀钢筋混凝土保护层锈胀开裂时间的预测模型[J].建筑结构学报,2010,31(2):85.
[6]ABOSRRA L,ASHOUR A F,YOUSEFFI M.Corrosion of steel reinforcement in concrete of different compressive strengths[J].Construction and Building Materials,2011,25(10):3915.
[7]CASTRO P,VELEVA L,BALANCAN M.Corrosion of reinforced concrete in a tropical marine environment and in accelerated tests[J].Construction and Building Materials,1997,11(2):75.
[8]袁迎曙,章鑫森,姬永生.人工气候与恒电流通电法加速锈蚀钢筋混凝土梁的结构性能比较研究[J].土木工程学报,2006,39(3):42.
[9]宋华,牛荻涛.电化学快速锈蚀与自然环境钢筋锈蚀的相似性分析[J].西安建筑科技大学学报(自然科学版),2009,41(4):508.
[10]JIN W L,LI Z Y,CHEN J,et al.Dynamic life prediction of RCstructures on multi-environmental time similarity method[J].Advanced Materials Research,2011,255/260:220.
[11]OTIENO M,BEUSHAUSEN H,ALEXANDER M.Chlorideinduced corrosion of steel in cracked concrete-part I:experimental studies under accelerated and natural marine environments[J].Cement and Concrete Research,2016,79:373.
[12]WANG X G,SONG X W,ZHANG M P,et al.Experimental comparison of corrosion unevenness and expansive cracking between accelerated corrosion methods used in laboratory research[J].Construction and Building Materials,2017,153:36.
[13]储炜,史苑芗,魏宝明.钢筋在混凝土模拟孔溶液及水泥净浆中的腐蚀电化学行为[J].南京化工学院学报,1995,17(3):14
[14]VU K T,STEWART M G.Predicting the likelihood and extent of reinforced concrete corrosion-induced cracking[J].Journal of Structural Engineering,2005,131(11):1681.
[15]VU K T,STEWART M G.Structural reliability of concrete bridges including improved chloride-induced corrosion models[J].Structural Safety,2000,22(4):313.