| 引用本文: | 俞小彤,常西栋,周文涛,廖迎娣,陈达.氯盐与硫酸盐复合侵蚀下钢筋混凝土锈裂行为[J].哈尔滨工业大学学报,2024,56(2):151.DOI:10.11918/202301045 |
| YU Xiaotong,CHANG Xidong,ZHOU Wentao,LIAO Yingdi,CHEN Da.Corrosion-induced cover cracking of reinforced concrete under combined chloride and sulfate attack[J].Journal of Harbin Institute of Technology,2024,56(2):151.DOI:10.11918/202301045 |
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| 氯盐与硫酸盐复合侵蚀下钢筋混凝土锈裂行为 |
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俞小彤1,2,常西栋1,周文涛1,廖迎娣1,2,陈达1,2
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(1.河海大学 港口海岸与近海工程学院,南京 210098;2.海岸灾害及防护教育部重点实验室(河海大学),南京 210098)
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| 摘要: |
| 为评估海洋、盐湖等环境中钢筋混凝土结构耐久性,通过试验与理论相结合探究氯盐与硫酸盐复合侵蚀下钢筋混凝土锈裂特性。通电腐蚀5%（质量分数）NaCl、5%NaCl+5%Na2SO4溶液中钢筋混凝土试件,对比分析混凝土表观形貌、钢筋锈蚀特征。设计伴随的混凝土腐蚀试验,类比保护层腐蚀劣化,分析混凝土力学性能。结果表明:硫酸盐的存在改变胀裂前混凝土形貌,使得单一氯盐侵蚀下的“白须”消失,表面粉化并出现盐结晶,延长胀裂时间;复合侵蚀下钢筋锈蚀率低于单一氯盐侵蚀,二者均显著低于法拉第定律理论值;锈胀裂缝宽度与钢筋锈蚀率线性相关,硫酸盐的存在增大裂缝随钢筋锈蚀发展的速率;通电环境中,受腐蚀混凝土的抗压强度先升高后降低,劈裂抗拉强度不断降低。提出受腐蚀混凝土的抗拉强度演化经验公式。在经典锈胀模型的基础上考虑锈蚀产物对裂缝的填充作用,并将硫酸盐的影响考虑至混凝土抗拉强度、钢筋腐蚀电流密度中,建立复合侵蚀下钢筋混凝土胀裂时间预测模型,并验证了模型的有效性。 |
| 关键词: 氯盐-硫酸盐侵蚀 混凝土腐蚀 锈胀力 胀裂时间 |
| DOI：10.11918/202301045 |
| 分类号:TU375 |
| 文献标识码:A |
| 基金项目:江苏省自然科学基金(BK20220981)；中国博士后科学基金(2021M701048)；江苏省卓越博士后计划(2022ZB183) |
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| Corrosion-induced cover cracking of reinforced concrete under combined chloride and sulfate attack |
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YU Xiaotong1,2,CHANG Xidong1,ZHOU Wentao1,LIAO Yingdi1,2,CHEN Da1,2
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(1.College of Harbour, Coastal and Offshore Engineering, Hohai University, Nanjing 210098, China; 2.Key Laboratory of Coastal Disaster and Protection (Hohai University), Ministry of Education,Nanjing 210098, China)
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| Abstract: |
| To evaluate the durability of reinforced concrete structures in marine, salt lakes, etc., this paper explored the characteristics of corrosion-induced cover cracking under combined chloride and sulfate attack by experimental and theoretical analysis. The reinforced concrete specimens were exposed to 5%NaCl, 5%NaCl+5%Na2SO4 solutions with electric field for degradation acceleration. The visual appearance of concrete and corrosion of reinforcement under different conditions were compared. Moreover, an accompanied experiment for concrete deterioration was designed in analogy to the cover deterioration, and the mechanical properties of concrete were analyzed. The results showed that in presence of sulfate, the concrete cover appearance altered before cracking; the "white whiskers" under the single chloride solution disappeared while efflorescence existed on the surface of the concrete with sulfate crystallization. Furthermore, the presence of sulfate also extented the time before corrosion-induced cracking. The corrosion level of the reinforcement under the combined attack was lower than that under the single chloride attack, and both were much lower than the predicted value by Faraday′s law. The crack width was linearly correlated with the corrosion level, and the presence of sulfates increased the development of crack width with the corrosion level. Under the electric field, the compressive strength of concrete increased at first and then decreased, while the tensile splitting strength reduced with exposure time. An empirical formula for the tensile strength of deteriorated concrete was proposed. The effect of filling rust products in the cracks was taken into account based on the classic model for corrosion-induced cover cracking. In addition, the effect of sulfate was considered in the tensile strength of concrete and corrosion current density. On these bases, a time prediction model for the corrosion-induced cracking of reinforced concrete under combined attack was established, and the validity of the model was verified. |
| Key words: combined sulfate-chloride attack concrete deterioration corrosion expansive pressure corrosion-induced cover cracking time |
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