اثر تغییرات غلظت کربن‌دی‌اکسید بر روی زمان شروع خوردگی سازه‌های بتن‌آرمه

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه مهندسی عمران، واحد تهران شرق، دانشگاه آزاد اسلامی، تهران، ایران

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

چکیده

نفوذ کربن دی اکسید تا سطح آرماتور در سازه‌های بتن‌آرمه، منجر به خوردگی آرماتورها می‌شود. میزان غلظت کربن دی اکسید در محیط برروی زمان شروع خوردگی اثرگذار است. بر اساس ادبیات فنی، میزان غلظت کربن دی اکسید موجود در جو می‌تواند بر اثر تغییرات آب وهوایی از  397 ppm در سال 2005 با نرخ‌های رشد متفاوتی به 1000 ppm درسال 2100 افزایش یابد. در این مقاله سعی شده است که با استفاده از روش مونت کارلو احتمال شروع خوردگی آرماتورهای سازه‌های بتنی در طی زمان محاسبه شود و همچنین اثر در نظر گرفتن تغییرات غلظت کربن دی اکسید در جو و میانگین دمای زمین، بر روی زمان شروع خوردگی، مورد توجه قرار گیرد و با حالتی که تغییرات عوامل مذکور برای محاسبه زمان شروع خوردگی در نظر گرفته نمی‌شود، مقایسه شود. بر اساس نتایج تحلیل‌ها، احتمال شروع خوردگی با در نظر گرفتن هر یک از دو سناریوی معتبر برای افزایش غلظت کربن دی اکسید، تفاوت چندانی نمی‌کند. اما مقایسه نتایج حالت‌هایی که غلظت کربن دی اکسید متغیر می‌باشد با حالتی که غلظت کربن دی اکسید ثابت در نظر گرفته شود نشان داد که احتمال شروع خوردگی در یک زمان مشخص برای هر یک از حالات غلظت ثابت و متغیر کربن دی اکسید می‌تواند تفاوت قابل توجه‌ای داشته باشد. همچنین مشاهده شد که تغییرات میانگین دما اثر قابل توجه‌ای بر روی زمان شروع خوردگی ندارد.

کلیدواژه‌ها


عنوان مقاله [English]

The Effect of Changes in Carbon-Dioxide Concentrations on Corrosion Initiation of Reinforced Concrete Structures

نویسندگان [English]

  • M. Ghanooni Bagha 1
  • M.A Shayanfar 2
  • M.R Yekke fallah 2
1 Department of civil Engineering, East Tehran Branch, Islamic Azad University, Tehran, Iran
2 The Centre of Excellence for Fundamental Studies in Structural Engineering, Iran University of Science and Technology, Tehran, Iran
چکیده [English]

Carbon dioxide and carbonation in concrete structures after several years may leads to corrosion of the reinforcements, and consequently reduces the life of concrete structures. According to reports of Intergovernmental Panel on Climate Change (IPCC), uncertainty to predict the weather conditions is very high. The annual growth rate of carbon dioxide concentrations from 1.4 ppm during the period of 1960 to 2005 has increased to 1.9 ppm during the period of 1995 to 2005. Two predictions of A1F1 and A1B are presented for changes in carbon dioxide concentrations. In A1F1 high economic growth, population growth will continue in the mid-21st century with high speed, and the use of fossil fuels will also continue as before. In A1B, using clean energies is common. In fact, A1F1 and A1B are respectively pessimistic and optimistic predictions for the concentration of carbon dioxide in the environment. According the analysis results base on Monte Carlo simulation, global warming and climate change lead to an increase in average temperature of earth and atmospheric carbon dioxide concentrations, and finally, it can reduce the durability of concrete structures. Also, it was observed that ignoring changes in concentration of carbon dioxide can have a significant effect on the results obtained for carbonation depth. It was also observed that considering each of predictions for changes in carbon dioxide concentrations does not substantially influence the depth of carbonation.

کلیدواژه‌ها [English]

  • Carbonation
  • Climate Change
  • Monte Carlo Simulation
  • Carbon-Dioxide Concentrations
  • Temperature
[1] E. Sistonen, A. Cwirzen, J.J.C.S. Puttonen, Corrosion mechanism of hot-dip galvanised reinforcement bar in cracked concrete, Corrosion Science, 50(12) (2008) 3416-3428.
[2] M.A. Shayanfar, M.-A. Barkhordari, M.J.J.o.C.S.U. Ghanooni-Bagha, Probability calculation of rebars corrosion in reinforced concrete using css algorithms, Journal of Central South University, 22(8) (2015) 3141-3150.
[3] M.A. Shayanfar, M.A. Barkhordari, M.J.P.P.C.E. Ghanooni-Bagha, Estimation of corrosion occurrence in RC structure using reliability based PSO optimization, Periodica Polytechnica. Civil Engineering, 59(4) (2015) 531-542.
[4] M. Ghanooni-Bagha, M. Shayanfar, A. Shirzadi-Javid, H.J.C. Ziaadiny, B. Materials, Corrosion-induced reduction in compressive strength of self-compacting concretes containing mineral admixtures, Construction and Building Materials, 113 (2016) 221-228.
[5] M.A. Shayanfar, M.A. Barkhordari, M.J.A.i.S.E. Ghanooni-Bagha, Effect of longitudinal rebar corrosion on the compressive strength reduction of concrete in reinforced concrete structure, Advances in Structural Engineering, 19(6) (2016) 897-907.
[6] A.A. Ramezanianpour, Recommendations and proposals for concrete durability and islands off the coast of southern (In Persian), Road, Housing and Development Research Center, Iran, 1992.
[7] A.V. Saetta, R.V. Scotta, R.V.J.M.J. Vitaliani, Analysis of chloride diffusion into partially saturated concrete, ACI Materials Journal, 90(5) (1993) 441-451.
[8] N.a.S. Nakicenovic, R., Special Report on Emissions Scenarios, Edited by NebojsaNakicenovic and Robert Swart, 1, 2000.
[9] S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, H.L. Miller, Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change, 2007, in, Cambridge University Press, Cambridge, 2007.
[10]
E. Bastidas-Arteaga, F. Schoefs, M.G. Stewart, X.J.E.S. Wang, Influence of global warming on durability of corroding RC structures: A probabilistic approach, Engineering Structures, 51 (2013) 259-266.
[11] M.G. Stewart, X. Wang, M.N.J.E.S. Nguyen, Climate change impact and risks of concrete infrastructure deterioration, Engineering Structures, 33(4) (2011) 1326-1337.
[12] M.G. Stewart, X. Wang, M.N.J.S.S. Nguyen, Climate change adaptation for corrosion control of concrete infrastructure, Structural Safety, 35 (2012) 29-39.
[13] X. Wang, M.G. Stewart, M.J.C.c. Nguyen, Impact of climate change on corrosion and damage to concrete infrastructure in Australia, Climatic Change, 110(3-4) (2012) 941-957.
[14] A. Lindvall, Duracrete–probabilistic performance based durability design of concrete structures, in: 2nd Int. PhD. Symposium in civil engineering, 1998.
[15] I.-S. Yoon, O. Çopuroğlu, K.-B.J.A.e. Park, Effect of global climatic change on carbonation progress of concrete, Atmospheric environment, 41(34) (2007) 7274-7285.
[16] M. Akiyama, D.M. Frangopol, I.J.E.S. Yoshida, Time-dependent reliability analysis of existing RC structures in a marine environment using hazard associated with airborne chlorides, Engineering Structures, 32(11) (2010) 3768-3779.
[17] D.V. Val, P.A.J.R.E. Trapper, S. Safety, Probabilistic evaluation of initiation time of chloride-induced corrosion, Reliability Engineering & System Safety, 93(3) (2008) 364-372.
[18] S. Engelund, L. Mohr, C. Edvardsen, General guidelines for durability design and redesign: duracrete, probabilistic performance based durability design of concrete structures, CUR, 2000.
[19] K.A.T. Vu, M.G.J.S.s. Stewart, Structural reliability of concrete bridges including improved chloride-induced corrosion models, Structural Safety, 22(4) (2000) 313-333.
[20] A.M. Neville, Properties of concrete, 3rd ed ed., Longman Scientific & Technical, 1981.
[21] M.A. Shayanfar, Ghanooni-Bagha, M., Jahani, E, Reliability theory of structures (In Persian), IUST Publication, Tehran, Iran, 2016.
[22] J.c.o.s. safety, Code, J.P.M., in, 2001.
[23] L.J.I.o.E.C.E.T. Pham, Reliability analyses of reinforced concrete and composite column sections under concentric loads, Institution of Engineers (Australia) CivEng Trans, (1) (1985).
[24] S.A. Mirza, J.G. MacGregor, M.J.J.o.t.S.D. Hatzinikolas, Statistical descriptions of strength of concrete, Journal of the Structural Division, 105(ASCE 14628 Proceeding)(6) (1979) 1021-1037.
[25] T.M. Wigley, R. Richels, J.A.J.N. Edmonds, Economic and environmental choices in the stabilization of atmospheric CO2 concentrations, Nature, 379(6562) (1996) 240.
[26] M.R. Allen, W.J.J.N. Ingram, Constraints on future changes in climate and the hydrologic cycle, Nature, 419(6903) (2002) 224-232.
[27] F.N. Sperling, R. Washington, R.J.J.C.C. Whittaker, Future climate change of the subtropical North Atlantic: implications for the cloud forests of Tenerife, Climatic Change, 65(1-2) (2004) 103-123.
[28] P. Lemke, Ren, R. and Alley, I., The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report, Climate Change, 4 (2007) 2007.