بررسی تأثیر افزایش دما بر روی بتن های حاوی فنر فلزی بازیافتی و مقایسه با الیاف های رایج

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشیار، دانشگاه سمنان، سمنان، ایران

2 دانشجوی دکترای سازه دانشگاه سمنان

چکیده

استفاده از الیاف یا مواد بازیافتی در بتن، باعث بهبود مقاومت، شکل‌پذیری و دوام بتن می‌شود. بتن دارای خواص ضد حریق بوده لکن بیشترین نگرانی از سازه‌های بتن‌آرمه در زمان آتش‌سوزی مربوط به میلگردها است. لذا یکی از پیشنهادات به منظور کاهش خطرات فوق، استفاده از مصالح جایگزین نظیر فنر فلزی بازیافتی می باشد. در این مقاله به مطالعه‌ی آزمایشگاهی عملکرد بتن‌های حاوی فنر فلزی بازیافتی با بکار بردن درصدهای حجمی 2/0، 4/0 و 6/0 تحت دماهای 25، 100، 250، 500، 700 و 900 درجه‌ی سانتی‌گراد پرداخته شد. پس از سرد شدن نمونه‌ها، مقاومت فشاری و کششی بهینه‌ترین درصد اختلاط فنر در بتن، با بتن حاوی الیاف فولادی و پلی‌پروپیلن مقایسه شد. نتایج حاکی از آن است که استفاده از مقدار 2/0 درصد فنر در بتن با باعث بهبود مقاومت فشاری و کششی بتن تا حدود 3 برابر نمونه‌ی شاهد شده، اما هرچه میزان استفاده از آن در بتن افزایش یابد از مقاومت آن نیز کاسته می‌شود. همچنین مقاومت فشاری بتن با درصد بهینه‌ی فنر در دماهای مختلف حدود 2 الی 3 برابر بتن حاوی الیاف فولادی و پلی‌پروپیلن بوده و مقاومت کششی آن نیز تا حدودی نزدیک به مقاومت الیاف فولادی می‌باشد. همچنین وجود فنر در بتن، عرض ترک‌های بوجود آمده پس از انجام تست مقاومت کششی را تا 3 برابر کاهش می‌دهد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

.Assessing Effect of Temperature Rise on the Concrete Containing Recycled Metal Spring and Its Comparison with Ordinary Fibres

نویسندگان [English]

  • Madjid Gholhaki 1
  • Ghasem Pachideh 2
1 Associate Professor, Faculty of Civil Engineering, Semnan University, Semnan, Iran
2 Semnan University
چکیده [English]

Fibre or recycled material used in the concrete improves resistance, ductility, and durability of concrete. Concrete has fire-resistant properties but the most worrying thing about reinforced concrete structures during the fire is related to rebars. Therefore, there is a suggestion about use of alternative materials such as recycled metal spring in order to reduce above mentioned risks. In this paper, we conduct laboratory study to assess performance of concrete containing recycled metal spring while using volumetric amounts of 0.2, 0.4 and 0.6% at temperatures of 25, 100, 250, 500, 700 and 900 degrees Celsius. Furthermore, compressive strength and tensile strength of the most optimal combination of spring in the concrete are compared with concrete containing steel fibre and polypropylene. The results show that spring used in the concrete improves compressive strength and tensile strength. But the more the spring is used in the concrete, the more the resistance is reduced. Therefore, if the spring with 0.2 volume percent that is considered as the most optimal combination percentage is increased by 3 times, it increases compressive strength and tensile strength. Furthermore, the optimal compressive strength of spring in different temperatures is about 2 – 3 times of steel fibre and polypropylene and its tensile strength is close to strength of steel fibre. Fibre used in concrete reduces width of the cracks created after the test by 3 times.

کلیدواژه‌ها [English]

  • spring concrete
  • compressive strength
  • tensile strength
  • recycled metal spring
  • steel fibre
  • polypropylene fibre
  • high temperatures
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