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

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نشریه مهندسی عمران امیرکبیر
دوره 50، شماره 4
مهر و آبان 1397
صفحه 697-706

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