بررسی زمان شروع خوردگی سازه‌های بتن ‌آرمه در فواصل مختلف از دریا

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشکده مهندسی عمران، دانشگاه علم و صنعت ایران، تهران، ایران

2 دانشکده مهندسی عمران، واحد تهران شرق، دانشگاه آزاد اسلامی، تهران، ایران

چکیده

یکی از آسیب­ هایی که در سازه ­های بتن آرمه به وجود می­ آید و باعث می­ شود که سازه مورد نظر عملکرد مورد انتظار را در هنگام وقوع زلزله محتمل نداشته باشد، خوردگی آرماتور می ­باشد. سازه­ های بتن آرمه نزدیک به ساحل، پل ­هایی که در معرض نمک یخ زدایی در فصل زمستان هستند، پایه ­های سازه­ های دریایی که تحت اثر جزر و مد هستند، از جمله مواردی است که خوردگی باعث آسیب در عملکرد مورد انتظار می ­شود. خوردگی بیشتر تحت دو عامل کلر (خوردگی حفره­ای) و کربناسیون (خوردگی یکنواخت) رخ می­ دهد. بعد از عبور این یون­ ها از پوشش فیزیکی (کاور بتنی) و پوشش شیمیایی (لایه محافظ غیرفعال دور میلگرد) به سطح میلگرد رسیده و خوردگی آغاز می­شود. در اثر خوردگی خصوصیات مکانیکی فولاد و بتن کاهش یافته و عملکرد لرزه­ای سازه را تحت تأثیر قرار می ­دهد. یکی از پارامترهای مهم در بررسی آثار خوردگی بر عملکرد لرزه ­ای در طول عمر مفید سازه، زمان شروع خوردگی می­ باشد. بر اساس قانون فیک زمان شروع خوردگی تابعی از کلرید سطحی، ضریب انتشار کلرید در بتن، پوشش بتنی روی آرماتورها و کلرید بحرانی می‌باشد. در این تحقیق خوردگی ناشی از کلر در نظر گرفته شده است. زمان شروع خوردگی در دو حالت غیراحتمالاتی و احتمالاتی مونت کارلو (با در نظر گرفتن عدم قطعیت‌ها­ در پارامترهای تأثیرگذار بر پیش‌بینی زمان شروع خوردگی) تعیین می‌شود. در پایان با مقایسه این دو حالت با یکدیگر میزان تأثیر عدم قطعیت‌ها در احتمال زمان شروع خوردگی نشان داده شده است. همچنین میزان اثر فاصله از دریا و نسبت آب به سیمان‌های متفاوت نیز در نظر گرفته شده است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Investigation of the corrosion initiation time of reinforced concrete structures at different distances from the Sea

نویسندگان [English]

  • Amirhossein Jafary 1
  • mohsen ali shayanfar 1
  • Mohammad Ghanooni-Bagha 2
1 Department of Civil engineering, Iran University of Science and Technology, Tehran, Iran
2 Department of Civil Engineering, East Tehran Branch, Islamic Azad University, Tehran, Iran
چکیده [English]

Corrosion is one of the crucial damages that may occur to reinforced concrete structures. It also may affect the expected performance of the structure during possible earthquakes. Onshore reinforced structures, bridges exposed to deicing salts in winter and also the pillars of marine structures under tidal waves, all of which are examples of corrosion damages. Corrosion mostly occurs due to two main reasons: chloride and carbonation which cause pitting corrosion and uniform corrosion, respectively. Corrosion starts with the reaching of those two ions to the bar surface, passing by the physical and chemical passive covers. Corrosion also affects the mechanical properties of the steel and the concrete and reduces the seismic performance of the structure. One of the most important parameters in studying corrosion and its effects on the seismic performance and life cycle of the structure is the corrosion initiation time. According to Fick’s law, the initiation time is a function of surface and critical chloride, chloride diffusion coefficient and concrete cover on armatures. In the present study, the chloride-based corrosion is considered. Besides, corrosion initiation time is determined by deterministic and probabilistic Monte-Carlo methods considering the uncertainties in the effective parameters. In the end, by comparing these two methods, the effect of uncertainties in the possibility of corrosion initiation time is presented. Furthermore, parameters like the distance from the sea and the water-to-cement ratio are discussed in a parametric study.

کلیدواژه‌ها [English]

  • Concrete structures
  • Corrosion
  • Corrosion initiation
  • Monte-Carlo Simulation
  • Uncertainties

مراجع

[1] E.A. Dizaj, R. Madandoust, M.M. Kashani, Probabilistic seismic vulnerability analysis of corroded reinforced concrete frames including spatial variability of pitting corrosion, Soil Dynamics and Earthquake Engineering, 114 (2018) 97-112.
[2] S. Ahmad, Reinforcement corrosion in concrete structures, its monitoring and service life prediction––a review, Cement and concrete composites, 25(4-5) (2003) 459-471.
[3] A. Neville, Chloride attack of reinforced concrete: an overview, Materials and Structures, 28(2) (1995) 63-70.
[4] T. Saad, C.C. Fu, Determining remaining strength capacity of deteriorating RC bridge substructures, Journal of Performance of Constructed Facilities, 29(5) (2015) 04014122.
[5] H. Li, B. Li, R. Jin, S. Li, J.-G. Yu, Effects of sustained loading and corrosion on the performance of reinforced concrete beams, Construction and Building Materials, 169 (2018) 179-187.
[6] M.A. Shayanfar, M.A. Barkhordari, M. Ghanooni-Bagha, Estimation of corrosion occurrence in RC structure using reliability based PSO optimization, Periodica Polytechnica Civil Engineering, 59(4) (2015) 531-542.
[7] K. Tuutti, Corrosion of steel in concrete, Cement-och betonginst., 1982.
[8] Y. Du, L. Clark, A. Chan, Effect of corrosion on ductility of reinforcing bars, Magazine of Concrete Research, 57(7) (2005) 407-419.
[9] H.-S. Lee, T. Noguchi, F. Tomosawa, Evaluation of the bond properties between concrete and reinforcement as a function of the degree of reinforcement corrosion, Cement and Concrete research, 32(8) (2002) 1313-1318.
[10] C. Fang, K. Lundgren, M. Plos, K. Gylltoft, Bond behaviour of corroded reinforcing steel bars in concrete, Cement and concrete research, 36(10) (2006) 1931-1938.
[11] S. Williamson, L. Clark, Pressure required to cause cover cracking of concrete due to reinforcement corrosion, Magazine of Concrete research, 52(6) (2000) 455-467.
[12] M.M. Kashani, P. Alagheband, R. Khan, S. Davis, Impact of corrosion on low-cycle fatigue degradation of reinforcing bars with the effect of inelastic buckling, International Journal of Fatigue, 77 (2015) 174-185.
[13] J. Wu, P.N. Faye, W. Zhang, B. Diao, Chloride diffusivity and service life prediction of RC columns with sustained load under chloride environment, Construction and Building Materials, 158 (2018) 97-107.
[14] J. Zhang, Z. Lounis, Sensitivity analysis of simplified diffusion-based corrosion initiation model of concrete structures exposed to chlorides, Cement and concrete research, 36(7) (2006) 1312-1323.
[15] T. Yang, B. Guan, G. Liu, Y. Jia, Modeling of chloride ion diffusion in concrete under fatigue loading, KSCE Journal of Civil Engineering, 23(1) (2019) 287-294.
[16] W. Shao, Y. Nie, F. Liang, D. Shi, A novel comprehensive evaluation method for the corrosion initiation life of RC hollow piles in chloride environments, Construction and Building Materials, 249 (2020) 118801.
[17] M.-A. Shayanfar, M.-A. Barkhordari, M. Ghanooni-Bagha, Probability calculation of rebars corrosion in reinforced concrete using css algorithms, Journal of Central South University, 22(8) (2015) 3141-3150.
[18] M. Ghanooni-Bagha, M.A. Shayanfar, M.R. Yekefallah, The Effect of Changes in Carbon-dioxide Concentrations on Corrosion Initiation of Reinforced Concrete Structures, Amirkabir J. Civil Eng, 9(4) (2018) 697-706.
[19] A. Chateauneuf, A. Messabhia, A. Ababneh, Reliability analysis of corrosion initiation in reinforced concrete structures subjected to chlorides in presence of epistemic uncertainties, Structural Safety, 86 (2020) 101976.
[20] A.A. Ramezanianpour, E. Jahangiri, F. Moodi, B. Ahmadi, Evaluation of Models for Service-Life Prediction of Reinforced Concrete Structures in Persian Gulf Marine Environment,  (2012).
[21] S.-K. Choi, R.A. Canfield, R.V. Grandhi, Estimation of structural reliability for Gaussian random fields, Structures and Infrastructure Engineering, 2(3-4) (2006) 161-173.
[22] V. Novokshchenov, Deterioration of reinforced concrete in the marine industrial environment of the Arabian Gulf—A case study, Materials and Structures, 28(7) (1995) 392-400.
[23] B. Saassouh, Z. Lounis, Probabilistic modeling of chloride-induced corrosion in concrete structures using first-and second-order reliability methods, Cement and Concrete Composites, 34(9) (2012) 1082-1093.
[24] J. Crank, The mathematics of diffusion, Oxford university press, 1979.
[25] A. Khitab, W. Anwar, M.T. Arshad, Predictive Models of Chloride Penetration in concrete: An Overview, MUST J. Eng. Appl. Sci, 1 (2017) 1-14.
[26] N.S. Berke, M.C. Hicks, Estimating the life cycle of reinforced concrete decks and marine piles using laboratory diffusion and corrosion data, in:  Corrosion forms and control for infrastructure, ASTM International, 1992.
[27] K. Takewaka, S. Mastumoto, Quality and cover thickness of concrete based on the estimation of chloride penetration in marine environments, Special Publication, 109 (1988) 381-400.
[28] P. Bamforth, W.F. Price, M. Emerson, International Review of Chloride Ingress Into Structural Concrete: A Trl Report (Trl 359),  (1997).
[29] R. McGee, Modelling of durability performance of Tasmanian bridges, ICASP8 applications of statistics and probability in civil engineering, 1 (1999) 297-306.
[30] V. Papadakis, A. Roumeliotis, M. Fardis, C. Vagenas, Mathematical modelling of chloride effect on concrete durability and protection measures, Concrete repair, rehabilitation and protection,  (1996) 165-174.
[31] M. Ghanoonibagha, M.A. Shayanfar, S. Asgarani, M. Zabihi Samani, Service-Life Prediction of Reinforced Concrete Structures In Tidal Zone, Journal Of Marine Engineering, 12(24) (2017) 13-22.
[32] A.A. Ramezanianpou, E. Jahangiri, F. Moodi, B. Ahmadi, Assessment of the Service Life Design Model Proposed by fib for the Persian Gulf Region, Journal of Oceanography, 5(17) (2014) 101-112.
[33] P.C. Hoffman, R.E. Weyers, Probabilistic durability analysis of reinforced concrete bridge decks, in:  Probabilistic Mechanics & Structural Reliability, ASCE, 1996, pp. 290-293.
[34] K.A.T. Vu, M.G. Stewart, Structural reliability of concrete bridges including improved chloride-induced corrosion models, Structural safety, 22(4) (2000) 313-333.
[35] M. Shekarchi, P. Ghods, R. Alizadeh, M. Chini, M. Hoseini, DURAPGULF, A LOCAL SERVICE LIFE MODEL FOR THE DURABILITY OF CONCRETE STRUCTURES IN THE SOUTH OF IRAN, Arabian Journal for Science & Engineering (Springer Science & Business Media BV), 33 (2008).
[36] M.P. Enright, D.M. Frangopol, Probabilistic analysis of resistance degradation of reinforced concrete bridge beams under corrosion, Engineering structures, 20(11) (1998) 960-971.
[37] S. B, Structural use of concrete–part 1, in:  code of practice for design and construction, 1999.
[38] R. Yu, L. Chen, D. Zhang, Z. Wang, Life cycle embodied energy analysis of RC structures considering chloride-induced corrosion in seismic regions, in:  Structures, Elsevier, 2020, pp. 839-848.
[39] M. GhAnooni-BAGhA, M.A. ShAyAnfAr, O. Reza-Zadeh, M. Zabihi-Samani, The effect of materials on the reliability of reinforced concrete beams in normal and intense corrosions, Eksploatacja i Niezawodność, 19(3) (2017).
نشریه مهندسی عمران امیرکبیر
دوره 55، شماره 2
اردیبهشت 1402
صفحه 389-406

فایل ها

هم رسانی

ارجاع به این مقاله

آمار