ارزیابی مقاومت فشاری و نفوذپذیری پوشش‌های محافظ ورق‌های CFRP تحت شرایط حاد محیطی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه بین‌المللی امام خمینی (ره)، قزوین، ایران

2 دانشکدة فنی و مهندسی، دانشگاه بین المللی امام خمینی (ره)

چکیده

در این مقاله نتایج بررسی تاثیر استفاده از پوشش‌های محافظ اعمال شده بر ورق‌های CFRP تقویت کننده‌ی بتن تحت شرایط حاد محیطی از جمله سیکل‌های تر و خشک ‌شدگی، یخ و ذوب یخ و تغییرات دما ارائه شده است. معمولا شرایط محیطی حاد موجب کاهش عملکرد ورق‌های CFRP، به دلیل افزایش نفوذپذیری و کاهش دوام آن می‌گردد. به منظور محافظت از ورق‌های CFRP چهار نوع ملات الیافی پایه سیمانی، ملات الیافی حاوی ماده هوازا، ملات ماسه سیمان حاوی چسب اپوکسی، ملات آب‌بند پایه اپوکسی بر روی سطح آن‌ها اجرا گردید نمونه‌های به کار گرفته شده در این بررسی‌ها، شامل نمونه‌های مکعبی 150 میلی‌متری بتن تقویت شده با ورق‌های CFRP در دو حالت با و بدون پوشش محافظ و نیز نمونه‌های مکعبی و منشوری ساخته شده از ملات (پوشش‌های محافظ) می‌باشند. آزمایش‌های انجام شده شامل آزمایش نفوذپذیری با به کارگیری روش "محفظه استوانه‌ای"، آزمایش جذب آب موئینه ملات و تعیین مقاومت فشاری ملات، قبل و بعد از قرار گرفتن نمونه‌ها تحت شرایط حاد می‌باشد. نتایج به دست آمده نشان می‌دهد که انتخاب مناسب پوشش محافظ تاثیر قابل ملاحظه‌ای بر دوام نمونه‌های تقویت شده با CFRP و کاهش نفوذپذیری آن‌ها تحت هر یک از شرایط حاد محیطی داشته است. به طوری که استفاده از این پوشش‌ها در نمونه‌های بتنی تقویت شده با ورق CFRP، تحت شرایط تر و خشک شدگی، یخ و ذوب یخ و تغییرات دما، موجب کاهش نفوذپذیری به میزان 28%، 34% و 36% شده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Assessing the compressive strength and permeability of protective coating layers applied to CFRP sheets, under harsh environmental conditions

نویسندگان [English]

  • Mahmood Naderi 1
  • roza rahbari 2
1 Department of civil engineering, Faculty of engineering, International Imam Khomeini university, Qazvin, Iran
2 Department of Civil Engineering, Engineering Faculty, International Imam Khomeini University, Qazvin, Iran
چکیده [English]

In this paper, the results of the effect of exposure of CFRP strengthened and coated 150mm concrete cubes to harsh environments are presented. The harsh environment included: wet-dry, freeze-thaw and different temperature change cycles. It is anticipated that the intended environmental conditions harm the performance of the CFRP sheet by reducing the compressive strength of concrete and, at the same time, increase its permeability. The test specimens used in this investigation included 150mm CFRP strengthened concrete cubes with and without protective coating layers. The methods employed were "Cylindrical Chamber" permeability, mortar capillary water absorption and mortar compressive strength tests. The results obtained tend to indicate that the proper selection of protective coating has a significant impact on the performance of the CFRP-coated concrete cubes that were under harsh environmental conditions. Application of suitable coatings onto the CFRP layer caused respective reductions of about 28%, 34%, and 36%, on the permeability of specimens after being exposed to specified wet-dry, freeze-thaw and temperature change cycles.

کلیدواژه‌ها [English]

  • Protective coating layer
  • CFRP
  • Permeability
  • capillary absorption
  • cylindrical chamber
  • Harsh environment
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