تاثیر پوشش محافظ بر مقاومت چسبندگی ورق های CFRP در بعضی شرایط محیطی

نوع مقاله : علمی - پژوهشی

نویسندگان

1 مهندسی عمران،دانشکده فنی و مهندسی،دانشگاه بین المللی امام خمینی (ره)، قزوین، ایران

2 استاد، دانشکده فنی و مهندسی، دانشگاه بین المللی امام خمینی (ره)، قزوین، ایران

چکیده

برای عملکرد موفق سازه های بتنی تقویت شده با ورق های CFRP ، مقاومت چسبندگی بلند مدت قابل اعتمادی مورد نیاز است. در این مقاله نتایج بررسی تاثیر استفاده از پوشش محافظ اعمال شده بر روی ورق های CFRP در افزایش مقاومت و چسبندگی این ورق‌ها تحت شرایط محیطی حاد ارایه گردیده است. شرایط محیطی در نظر گرفته شده عبارتند از: چرخه‌های تر وخشک شدگی، یخ و ذوب یخ و تغییرات دما. نتایج حاصله حاکی از آن است که مقاومت چسبندگی نمونه‌های تقویت شده با ورق CFRP بدون لایه محافظ، به میزان24، 40 و 75 درصد تحت شرایط چرخه ای تغییر دما، تر و خشک شدگی و یخ و ذوب یخ کاهش می یابد. به منظور محافظت از ورق های 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. آزمایش‌های انجام شده شامل اندازه گیری مقاومت چسبندگی با بکارگیری روش های "کشیدن از سطح" و "پیچش" و همچنین تعیین مقاومت فشاری ملات های پوششی محافظ، قبل و بعد از قرار گرفتن نمونه‌ها تحت شرایط حاد می‌باشند. نتایج به دست آمده نشان می‌دهد که انتخاب مناسب پوشش محافظ تاثیر قابل ملاحظه‌ای بر افزایش دوام و عملکرد چسبندگی نمونه های تقویت شده با CFRP تحت هر یک از شرایط حاد محیطی داشته است. بطوریکه با اعمال این پوشش‌ها در نمونه‌های بتنی تقویت شده با ورق های CFRP، تحت شرایط تغییر دما، تر وخشک شدگی و یخ و ذوب یخ مقاومت چسبندگی به میزان 12%، 22% و 84% نسبت به نمونه‌های بدون پوشش محافظ افزایش یافته است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

The effect of protective coating on the bond strength of CFRP sheets in some environmental conditions

نویسندگان [English]

  • roza rahbari 1
  • Mahmood Naderi 2
1 Dept. of Civil Engineering, Engineering Faculty, International Imam Khomeini University, Qazvin, Iran
2 Professor, Department of Civil Engineering, Engineering Faculty, International Imam Khomeini University, Qazvin, Iran
چکیده [English]

Reliable long-term bond durability is required in order to have successful performance of concrete structures reinforced with CFRP sheets. In this paper, the results of investigating the effect of using protective coating applied on CFRP sheets in increasing the strength and bond durability of these sheets under acute environmental conditions are presented. The environmental conditions considered are: wet-drying cycles, freeze- thaw and temperature changes. The results show that the bond durability of CFRP-reinforced specimens without protective layer is reduced by 24, 40 and 75% under cyclic conditions of temperature change, wet-dry and freeze-thaw. In order to protect CFRP sheets, four types of mortar were used, consisting of cement-based fiber mortar, fiber mortar with air Entrainment, cement-sand mortar containing epoxy adhesive and epoxy-based waterproof mortar were applied on their surface. Tests performed include measuring the bond strength using the "pull-off" and "twist-off" methods, as well as determining the compressive strength of the protective coating mortars, before and after exposing specimens to acute conditions. The results obtained tend to indicate that the proper selection of protective coating had a significant impact on the performance and bond durability of the CFRP coated concrete cubes that were under harsh environmental condition. By applying these coatings on concrete specimens reinforced with CFRP sheets, under conditions of temperature change, wet-drying and freeze-thaw, the bond strength increased by 12%, 22% and 84% compared to the specimens without protective coating.

کلیدواژه‌ها [English]

  • Protective coating layer CFRP sheet
  • bond strength
  • “pull-off”
  • “twist-off
  • harsh environmental conditions

مراجع

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  • تاریخ دریافت: 23 تیر 1399
  • تاریخ بازنگری: 13 شهریور 1399
  • تاریخ پذیرش: 09 مهر 1399

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