اثر حالت‌های مختلف نفوذ یون کلر بر مدل عمر تیر بتنی ناشی از شکست خمشی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه عمران، دانشکده صنعت و معدن چرام، دانشگاه یاسوج، چرام، ایران

2 گروه مهندسی عمران، دانشگاه صنعتی بیرجند، بیرجند، ایران

3 دانشکده صنعت و معدن، دانشگاه یاسوج، چرام،ایران.

10.22124/jcr.2021.18773.1494

چکیده

ارزیابی مدل عمر سازه های بتنی نقش موثری در تعیین برنامه های تعمیر و نگهداری و همچنین برآورد احتمال خرابی این سازه‌ها دارد. به منظور محاسبه مدل عمر، ابتدا باید عوامل مخرب محیطی و اثرات آنها بر سازه شناسایی شوند. یکی از مهمترین عواملی که بر دوام ومقاومت سازه‌های بتنی اثرگذار است خوردگی میلگردها است که عموماً بر اثر نفوذ یون کلر در بتن ایجاد می شود. بر اثر خوردگی میلگرد، از سطح موثر میلگردها کاسته شده و به مرور زمان با ایجاد ترکهایی در مقطع بتنی از سطح مقطع موثر بتن نیز کاسته می شود. در این تحقیق با در نظر گرفتن عدم قطعیتهای ذاتی و آماری پارامترهای موثر بر خوردگی، برای حالتهای مختلف نفوذ یون کلر، مدل عمر تیر بتنی مورد ارزیابی قرار گرفته است. بدین منظور با در نظر گرفتن موقعیت یک تیر به عنوان شاهتیر پل، سناریوهای مختلف نفوذ یون کلر از جهتهای مختلف مقطع تیر در نظر گرفته می شود و بر اساس هر سناریو زمانهای احتمالاتی آغاز خوردگی میلگردها، ایجاد ترکها و پوسته شدن بتن محاسبه شده و اثر رخداد هر رویداد بر مقاومت خمشی تیر در نظر گرفته می شود. نتایج نشان می‌دهد که در نظر گرفتن اثر پوسته شدن بتن موجب تفاوت تا 20 درصد در مقادیر پیش‌بینی شده برای مقاومت خمشی تیر بتنی می‌شود و ارزیابی واقع بینانه‌تری از عمر باقیمانده سازه بدست خواهد آمد. همچنین حالتهایی که موجب پوسته شدن مقطع فشاری بتن می گردد به دلیل کاهش عمق موثر مقطع حالت بحرانی تری در مدل عمر تیر بتنی دارند.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Effect of different states of chloride ion penetration in concrete on the life model due to flexural failure

نویسندگان [English]

  • Seyed Abbas Hosseini 1
  • Mansour Bagheri 2
  • Seyed Mehrab Ramezani 3
1 Assistant Professor in Structural Engineering, Faculty of Technology and Mining, Yasouj University, Choram, Iran .
2 Department of Civil Engineering, Birjand University of Technology, P.B. 9719866981, Birjand, Iran
3 Faculty of Technology and Mining/ Yasouj University/ Choram/Iran.
چکیده [English]

Evaluation of the life model of concrete structures has an effective role in determining maintenance programs as well as estimating the probability of failure of these structures. One of the most important factors that affect the durability and strength of concrete structures is the corrosion of rebars, which is generally caused by the penetration of chloride ions in concrete. Due to the corrosion of the rebar, the effective surface of the rebars is reduced and over time, by creating cracks in the concrete section, the effective concrete cross-section is also reduced. In this study, considering the inherent and statistical uncertainties of the parameters affecting corrosion, for different states of chloride ion penetration, the concrete beam life model has been evaluated. For this purpose, considering a concrete beam, different scenarios of chloride ion penetration from different directions of the beam cross-section is considered, and based on each scenario, the corrosion initiation time of rebars, cracks, and scaling of concrete are calculated and the effect of each event on The flexural strength of the beam is evaluated. The results show that considering the effect of concrete scaling causes a difference of up to 20% in the predicted values for the flexural strength of concrete beams and a more realistic assessment of the remaining life of the structure will be obtained. Also, the states that cause the compressive cross-section of the concrete to peel are more critical in the concrete beam life model due to the reduction of the effective depth.

کلیدواژه‌ها [English]

  • Life model
  • Reinforcement corrosion
  • chloride ingress
  • reinforced concrete beam
  • Probabilistic assessment

مراجع

  1. Ying, L. and A. Vrouwenvelder, Service life prediction and repair of concrete structures with spatial variability. Heron, 52 (4), 2007.
  2. Hosseini, S.A., Probabilistic Calculation of the Corrosion Initiation of steel reinforcement Using Reliability Methods. Concrete Research, 2019. 12(3): p. 137-145.
  3. Chen, S., et al., Life-cycle modelling of concrete cracking and reinforcement corrosion in concrete bridges: A case study. Engineering Structures, 2021. 237: p. 112143.
  4. Zhang, L., et al., Corrosion rate models of reinforcement in modified coral aggregate concrete. Construction and Building Materials, 2021. 288: p. 123099.
  5. James, A., et al., Rebar corrosion detection, protection, and rehabilitation of reinforced concrete structures in coastal environments: A review. Construction and Building Materials, 2019. 224: p. 1026-1039.
  6. ACI308R-16, Guide to External Curing of Concrete. 2016, American Concrete Institute Farmington Hills, Mich.
  7. Regulations, O.o.N.B., Part 9 of National Regulations: Design and implementation of reinforced concrete buildings. 2014, Toseeh Iran: Tehran.
  8. Bhargava, K., et al., Modeling of time to corrosion-induced cover cracking in reinforced concrete structures. Cement and Concrete Research, 2005. 35(11): p. 2203-2218.
  9. Alexander, M. and H. Beushausen, Durability, service life prediction, and modelling for reinforced concrete structures–review and critique. Cement and Concrete Research, 2019. 122: p. 17-29.
  10. Van Beek, A., et al. Validation model for service life prediction of concrete structures. in 2nd International RILEM workshop on life prediction and aging management of concrete structures, Paris, France. 2003.
  11. Markeset, G. and M. Kioumarsi, Need for further development in service life modelling of concrete structures in chloride environment. Procedia engineering, 2017. 171: p. 549-556.
  12. Song, H.-W., et al., A micro-mechanics based corrosion model for predicting the service life of reinforced concrete structures. International Journal of Electrochemical Science, 2007. 2: p. 341-354.
  13. Safehian, M. and A.A. Ramezanianpour, Assessment of service life models for determination of chloride penetration into silica fume concrete in the severe marine environmental condition. Construction and Building Materials, 2013. 48: p. 287-294.
  14. Pang, L. and Q. Li, Service life prediction of RC structures in marine environment using long term chloride ingress data: Comparison between exposure trials and real structure surveys. Construction and Building Materials, 2016. 113: p. 979-987.
  15. Lin, G., Y. Liu, and Z. Xiang, Numerical modeling for predicting service life of reinforced concrete structures exposed to chloride environments. Cement and concrete composites, 2010. 32(8): p. 571-579.
  16. Ožbolt, J., G. Balabanić, and M. Kušter, 3D Numerical modelling of steel corrosion in concrete structures. Corrosion science, 2011. 53(12): p. 4166-4177.
  17. Yang, C., L. Li, and J. Li, Service life of reinforced concrete seawalls suffering from chloride attack: Theoretical modelling and analysis. Construction and Building Materials, 2020. 263: p. 120172.
  18. Khatri, R. and V. Sirivivatnanon, Characteristic service life for concrete exposed to marine environments. Cement and concrete research, 2004. 34(5): p. 745-752.
  19. Rodriguez, J., L. Ortega, and J. Casal, Load carrying capacity of concrete structures with corroded reinforcement. Construction and building materials, 1997. 11(4): p. 239-248.
  20. Andrade, C., J. Sarria, and C. Alonso, Corrosion Rate Field Monitoring of Post – Tensioned Tendons in Contact with Chlorides. Durability of Building Materials and Components, 1996. 2: p. 959–967.
  21. Bhargava, K., et al., Ultimate flexural and shear capacity of concrete beams with corroded reinforcement. Structural Engineering and Mechanics, 2007. 27(3): p. 347-363.
  22. Vu, K.A. and M.G. Stewart, Predicting the likelihood and extent of reinforced concrete corrosion-induced cracking. Journal of structural engineering, 2005. 131(11): p. 1681-1689.
  23. Khan, I., R. François, and A. Castel, Prediction of reinforcement corrosion using corrosion induced cracks width in corroded reinforced concrete beams. Cement and concrete research, 2014. 56: p. 84-96.
  24. Thoft-Christensen, P., Corrosion and cracking of reinforced concrete, in Life-Cycle Performance of Deteriorating Structures: Assessment, Design and Management. 2004. p. 26-36.
  25. Vidal, T., A. Castel, and R. François, Analyzing crack width to predict corrosion in reinforced concrete. Cement and concrete research, 2004. 34(1): p. 165-174.
  26. Nowak, A.S. and K.R. Collins, Reliability of structures. 2012: CRC Press.
  27. Zhao, Y., Y. Wang, and J. Dong, Experimental Study and Analytical Model of Concrete Cover Spalling Induced by Steel Corrosion. Journal of Structural Engineering, 2020. 146(6): p. 04020098.
  28. Hariche, L., et al., Effects of reinforcement configuration and sustained load on the behaviour of reinforced concrete beams affected by reinforcing steel corrosion. Cement and Concrete Composites, 2012. 34(10): p. 1202-1209.

29.          Malumbela, G., P. Moyo, and M. Alexander, Structural behaviour of beams under simultaneous load and steel corrosion, in Concrete Repair, Rehabilitation and Retrofitting II. 2008, CRC Press. p. 271-272.

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