بررسی میدانی و ریزساختاری آسیب‌پذیری اسکله‌های بتنی مسلح در برابر نفوذ یون کلرید در محیط دریایی خلیج‌فارس (مطالعه موردی: اسکله بندرعباس)

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشیار، دانشکده فنی، دانشگاه هرمزگان.

2 ایران، هرمزگان، بندرعباس،

10.22124/jcr.2025.30673.1701

چکیده

سازه‌های بتنی مسلح در محیط‌های دریایی به‌ویژه در سواحل خلیج‌فارس، در معرض تخریب تدریجی ناشی از نفوذ یون کلرید و کربناتاسیون قرار دارند. شرایط اقلیمی گرم و مرطوب، تبخیر بالا، پاشش مستقیم آب دریا و آلودگی‌های صنعتی، محیطی به‌شدت خورنده را برای این سازه‌ها فراهم کرده است. پژوهش حاضر با هدف بررسی میدانی و ریزساختاری آسیب‌پذیری اسکله‌های بتنی، به مطالعه موردی اسکله‌های بندرعباس می‌پردازد. به‌منظور تحلیل دقیق مکانیزم‌های تخریب، آزمایش‌هایی نظیر تعیین پروفیل نفوذ یون کلرید، بررسی میکروسکوپی با استفاده از تصاویر SEM، تحلیل عنصری با طیف‌سنجی پراش انرژی پرتوایکس (EDX) و اندازه‌گیری مقاومت فشاری بتن بر روی نمونه‌های برداشت‌شده و آزمایشگاهی انجام شده است. بر اساس نتایج بدست آمده نفوذ یون کلرید به درون بتن، عامل اصلی تخریب زودهنگام سازه‌های دریایی در محیط دریایی خلیج فارس است. این یون‌ها با ایجاد ترکیبات ناپایدار نظیر نمک فریدل و تضعیف ژل/ نانوساختار C-S-H، به‌طور مستقیم موجب افزایش تخلخل، کاهش انسجام ریزساختار، و افت مقاومت مکانیکی بتن می‌شوند. تصاویر میکروسکوپی (SEM) و تحلیل‌های عنصری (EDX) حاکی از تمرکز بالای یون کلرید، ترک‌های ریز و آسیب به ناحیه انتقالی سطحی بین خمیر سیمان و سنگدانه‌ها است. مشاهده پروفیل‌های نفوذ کلرید، بیانگر عبور غلظت یون‌ها از حد بحرانی خوردگی در عمق‌هایی بیش از 100 میلی‌متر است که نشان‌دهنده ضعف در طرح اختلاط، تراکم و عمل‌آوری بتن است. همچنین نتایج نشان داد که وجود پوشش‌های طبیعی نظیر صدف دریایی و افزایش ضخامت لایه پوششی بتن، در کاهش میزان نفوذ کلرید مؤثر بوده و نقش حفاظتی چشمگیری ایفا می‌کند.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Field and Microstructural Investigation of the Vulnerability of Reinforced Concrete Wharves to Chloride Ion Penetration in the Marine Environment of the Persian Gulf

نویسندگان [English]

  • mohammad amiri 1
  • Bahrami Goorbandi Bahrami Goorbandi 2
1 Associate Professor, University of Hormozgan, Faculty of Engineering, Bandar Abbas, Iran
2 Master Student, Civil Engineering, Islamic Azad University, Bandar Abbas Branch, Iran.
چکیده [English]

Reinforced concrete structures in marine environments, particularly along the Persian Gulf coasts, are susceptible to gradual deterioration caused by chloride ion penetration and carbonation. The hot and humid climate, high evaporation rates, direct seawater splash, and industrial pollutants create a highly aggressive environment for these structures. The present study aims to investigate the field performance and microstructural vulnerability of reinforced concrete wharves through a case study of the Bandar Abbas ports. To comprehensively analyze the degradation mechanisms, several tests were conducted on both field-extracted and laboratory-prepared specimens, including chloride ion penetration profiling, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and compressive strength testing. The results indicate that chloride ion ingress is the primary factor responsible for the premature deterioration of marine structures in the Persian Gulf. These ions contribute to the formation of unstable compounds such as Friedel's salt and weaken the C-S-H gel/nanostructure, directly leading to increased porosity, reduced microstructural integrity, and loss of mechanical strength. SEM images and EDX elemental analyses revealed high concentrations of chloride ions, microcracks, and damage to the interfacial transition zone (ITZ) between the cement paste and aggregates. Chloride penetration profiles showed ion concentrations exceeding the critical corrosion threshold at depths greater than 100 mm, indicating deficiencies in mix design, compaction, and curing practices. Moreover, the results demonstrated that natural coverings such as marine shells and increased concrete cover thickness significantly reduce chloride ingress and play an effective protective role.

کلیدواژه‌ها [English]

  • Concrete degradation
  • wharf
  • aggressive environment
  • structural repair
  • chloride ion
  • Bandar Abbas

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