پتانسیل خوردگی میلگرد در ملات‌های سرباره و پومیس قلیافعال

نوع مقاله : علمی - پژوهشی

نویسندگان

1 گروه مهندسی عمران، دانشکده مهندسی عمران و منابع زمین، واحد تهران مرکزی، دانشگاه آزاد اسلامی، تهران، ایران

2 دانشکده مهندسی عمران و محیط زیست و رئیس مرکز تحقیقات تکنولوژی و دوام بتن، دانشگاه صنعتی امیرکبیر، تهران، ایران

چکیده

تحقیقات پیشین نشان داده است که به دلیل چسبندگی مناسب می‌توان از مصالح قلیافعال به عنوان روکش محافظ سازه‌های بتنی استفاده نمود و با ایجاد یک لایه سطحی مصالح قلیافعال بر روی بتن، تا حد زیادی از مزایای این تکنولوژی جدید بهره جست. با این حال خواص مکانیکی و دوام مصالح قلیافعال هنوز کاملاً مشخص نیست. در این مقاله به بررسی مقاومت فشاری، مقاومت چسبندگی، نفوذ آب تحت فشار و پتانسیل خوردگی نیم پیل ملات های قلیافعال حاوی سرباره و پومیس به عنوان روکش بتن پرداخته شده است. نتایج نشان می دهد در آزمایش های مقاومت فشاری، مقاومت چسبندگی، نفوذ آب تحت فشار و پتانسیل خوردگی نیم پیل، عملکرد ملات های سرباره قلیافعال مناسب‌تر از ملات‌های سیمان پرتلندی بوده و استفاده از هیدروکسیدپتاسیم به عنوان فعالساز و مخلوط 90 درصد سرباره و 10 درصد پومیس به عنوان ماده پایه باعث دستیابی به بیشترین مقاومت فشاری و چسبندگی و کمترین نفوذپذیری و پتانسیل خوردگی میلگرد شده است. پتانسیل نیم پیل اولیه آزمونه‌های ملات قلیافعال بطور متوسط 1.9 برابرِ آزمونه‌های سیمان پرتلندی بوده است. این تفاوت نشان می دهد معیارهای ارائه شده در استاندارد ASTM C876 در خصوص ارتباط خطر خوردگی میلگردها و میزان پتانسیل نیم پیل برای آزمونه های قلیافعال قابل استفاده نبوده و نیاز است محدوده های دیگری برای مصالح قلیافعال ارائه گردد. همچنین بدلیل رسانایی بسیار متفاوت ملات های قلیافعال و سیمان پرتلندی، اعمال اختلاف پتانسیل به منظور تسریع نفوذ یون های کلراید و مقایسه عملکرد محصولات قلیافعال با سیمان پرتلندی روش مناسبی نمی باشد. ولی این روش برای مقایسه چندین طرح ملات قلیافعال مناسب بوده و روند نتایج آن مطابق با آزمایش های تسریع نشده بوده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Rebar Corrosion Potential in Alkali-Activated Slag and Pumice Mortars

نویسندگان [English]

  • Mohsen Jafari Nadoushan 1
  • Ali Akbar Ramezanianpour 2
1 Department of Civil Engineering, Faculty of Civil and Earth Resources Engineering, Central Tehran Branch, Islamic Azad University, Tehran, Iran
2 Concrete Technology and Durability Research Center (CTDRc), Department of Civil & Environmental Engineering, Amirkabir University of Technology, Tehran, Iran
چکیده [English]

Previous researches have shown that due to its good adhesion, alkali-activated materials can be used as a protective overlay for concrete structures. However, the mechanical properties and durability of alkali-activated materials are not fully investigated. In this paper, compressive strength, bond strength, water penetration and half-cell corrosion potential of alkali-activated slag and pumice mortars as concrete overlay are investigated. The results show that the performance of alkali-activated slag mortar is better than Portland cement one in above tests and the use of potassium hydroxide as activator and a mixture of 90% slag and 10% pumice as based material result in the highest compressive strength and bond strength and the lowest water permeability and half-cell corrosion potential. The initial half-cell potential reading of alkali-activated mortar specimens was an average of 1.9 times more than Portland cement mortar specimens. This difference indicates that the ranges presented in ASTM C876 and their relationship with rebar corrosion risks are not applicable for alkali-activated materials and it is necessary to provide other criteria for these materials. Also, due to different conductivity of alkali-activated and Portland cement mortars, applying potential difference to accelerate the penetration of chloride ions and comparing the performance of alkali-activated materials with Portland cement is not a correct method. However, this method is suitable for comparing mixes design of alkali-activated mortars and the its results are in accordance with non-accelerated methods.

کلیدواژه‌ها [English]

  • Alkali Activated
  • Slag
  • Pumice
  • Water Penetration
  • Corrosion Potential
  • Half-cell
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