تخمین نفوذپذیری ورق های GFRP تقویت کننده بتن، تحت شرایط محیطی حاد به روش "محفظه استوانه ای"

نوع مقاله : علمی - پژوهشی

نویسندگان

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

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

3 کارشناسی ارشد، دانشکده فنی و مهندسی، دانشگاه بین المللی امام خمینی (ره)، قزوین، ایران

10.22065/jsce.2020.195360.1912

چکیده

امروزه ورق های کامپوزیتی GFRP به عنوان یکی از مؤثرین مواد کامپوزیتی شناخته شده است، که به منظور تعمیر، تقویت و افزایش ظرفیت باربری سازه های بتنی مورد استفاده قرار می گیرد. با توجه به وزن سبک ، مقاومت در برابر خوردگی ، استحکام کششی بالا و سهولت استفاده بدون ایجاد وقفه در کاربری سازه، استفاده از این ورق ها بسیار گسترده شده است. در سال های اخیر ، برخی سازمان ها در ایران برای مقاوم سازی و محافظت از سازه های بتنی خود که در مناطق حاشیه خلیج فارس قرار دارند، استفاده از ورق های GFRP را انتخاب نموده اند. از این رو در مقاله حاضر، نتایج آزمایش نفوذپذیری انجام شده بر نمونه های تقویت شده با GFRP با استفاده از روش تازه توسعه یافته "محفظه استوانه ای" مورد بحث و بررسی قرار گرفته است. با توجه به اینکه زوال سازه های بتنی ناشی از نفوذ آب که در معرض شرایط حاد محیطی قرار دارند، مسئله ای مهم می باشد، پیش از اندازه گیری نفوذپذیری، نمونه های اشاره شده در بالا، تحت چرخه های مختلف تر وخشک، دمای بالا و پایین و یخ و ذوب یخ قرار می گیرند. نتایج حاصله بیانگر آنست که چرخه های تغییرات دما تاثیر اندک و چرخه های یخ و ذوب یخ، و تر و خشک شدن تاثیر بیشتری بر نفوذپذیری GFRP داشته است. میزان آب نفوذیافته پس از 30، 90، 150 سیکل در شرایط تر وخشک به ترتیب 61%، 100% ، 18% بیشتر از مقادیر بدست آمده از شرایط تغییر دما می باشد. با توجه به شرایط یخ و ذوب یخ نیز ، تمایل به افزایش نفودپذیری نمونه ها در سیکل های مشابه یخ و ذوب یخ به ترتیب در حدود 12%، 36% و 29% نسبت به شرایط تغییر دما مشاهده شد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Estimation of the Permeability of GFRP Sheet Reinforced Concrete, Under Extreme Environments, Using "Cylindrical Chamber" Method

نویسندگان [English]

  • Mahmood Naderi 1
  • Roza Rahbari 2
  • Mohammad Mahdi Shahmohammadi 3
1 Professor, Department of Civil Engineering, Engineering Faculty, International Imam Khomeini University, Qazvin, Iran
2 Ph.D. Student in Structural Engineering, Department of Civil Engineering, Engineering Faculty, International Imam Khomeini University, Qazvin, Iran
3 MSc in Structural Engineering, Department of Civil Engineering, Engineering Faculty, International Imam Khomeini University, Qazvin, Iran
چکیده [English]

Nowadays, the glass fiber-reinforced polymer (GFRP) sheets have been known to be one of the most effective composite materials that are used to increase the strength and durability of concrete structures. Owing to the light weight, corrosion resistance, high tensile strength and the ease of application without any interruption of the services, the use of these sheets has become very wide spread. In recent years, some organizations in Iran have opted for the use of GFRP sheets for the strengthening and protection of their concrete structures that are located in the areas exposed to the Persian Gulf water. Therefore, in the present paper, the results of the permeability tests conducted on GFRP strengthened concrete samples, using the newly developed “Cylindrical chamber” method are discussed. Since the deterioration of concrete structures exposed to extreme environmental conditions due to the water penetration, appears to be a critical issue, the above mentioned samples have been exposed to different cycles of wet-dry, high and low temperatures and freeze- thaw tests, before measuring their permeability’s.  The results showed that the temperature change cycles have a small effect on the permeability of GFRP in comparison to the freeze-thaw and wet-dry cycles. The penetrated volume of water after 30, 90, 150 wet-dry cycles, was 61%, 100%, 18% lower than the respective values obtained after the same cycles of temperature changes. Considering the freeze-thaw conditions it was found that similar cycles of freeze-thaw tend to increase the permeability of the samples by about 12%, 36%, 29%, compared with the respective values of the temperature change conditions.

کلیدواژه‌ها [English]

  • Permeability
  • GFRP
  • Cylindrical chamber
  • freeze- thaw
  • wet-dry
  • Temperature changes
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