مهندسی سازه و ساخت

مهندسی سازه و ساخت

ارزیابی خواص مکانیکی پسا‌حریق بتن سازه‌ای سبک و الیافی

نوع مقاله : علمی - پژوهشی

نویسندگان
1 دانشجوی دکتری، گروه مهندسی عمران، واحد شاهرود، دانشگاه آزاد اسلامی، شاهرود، ایران
2 استادیار، گروه مهندسی عمران، واحد شاهرود، دانشگاه آزاد اسلامی، شاهرود، ایران
3 دکتری مهندسی عمران، دانشکده عمران و محیط زیست (آزمایشگاه بتن و مصالح ساختمانی)، دانشگاه صنعتی امیرکبیر، تهران، ایران
چکیده
بتن در حرارت‌های بالا به جهت تنش‌های حرارتی بالا و مقاومت کششی پایین آن دچار مشکلاتی از قبیل ترک‌خوردگی، قلوه‌کن شدن یا خرابی می‌شود. در این تحقیق، به روش آزمایشگاهی و با استفاده از الیاف فولادی و پلی‌پروپیلن نمونه‌های بتنی تقویت شده است و تحت دماهای مختلف از 25 درجه تا 800 درجه سانتی‌گراد قرار گرفته است و آزمون‌های مقاومت فشاری، کششی و خمشی برای تعیین مشخصات مکانیکی بر روی نمونه‌ها انجام شده است. همچنین جهت ارزیابی تاثیر الیاف بر رفتار بتن سبک، نمونه بدون الیاف بعنوان مرجع، آزمایش شد. جهت بررسی بهتر نتایج، یک نمونه بتن حاوی سبکدانه نیز تهیه و در کنار سایر نمونه‌ها مورد آزمایش قرار گرفت. نتایج نشان می‌دهد که با اضافه شدن الیاف فولادی و پلی‌پروپیلن، مقاومت فشاری تا دمای 200 درجه بیش‌تر از نمونه شاهد یا مشابه آن است. همچنین نتایج مقاومت کششی نشان می‌دهد که نمونه‌های حاوی الیاف فولادی در تمامی سنین بیش‌ترین میزان مقاومت کششی را داشته است. نتایج مقاومت فشاری و کششی نمونه بتنی حاوی سبکدانه نیز نشان می‌دهد که در دماهای 600 درجه به بالا، نمونه بتن سبک دارای مقاومت بالاتر و یا قابل مقایسه با نمونه شاهد است. الیاف پلی‌پروپیلن در دمای 400 درجه شروع به ذوب شدن می‌کند که این باعث افت مقاومت فشاری و کششی در نمونه‌های حاوی این نوع الیاف در دمای بالاتر از 400 درجه شده است. در مجموع در بین هر چهار نوع بتن، براساس نتایج آزمایشگاهی بدست آمده و با نگاهی به مسائل اجرایی و سازه‌ای می‌توان بتن الیافی حاوی الیاف فلزی را مناسب‌ترین گزینه جهت اجرای سازه‌هایی که خطر قرارگیری در معرض آتش و دماهای بالا در آنها وجود دارد، دانست.
کلیدواژه‌ها

موضوعات


عنوان مقاله English

Investigation of the mechanical properties of structural lightweight concrete and fiber reinforced concrete exposed to elevated temperatures

نویسندگان English

Khalil Arab Shahrab 1
Aboozar Mirzakhani 2
Ehsan Kashi 2
Nematollah Bakhshi 3
1 Ph.D Candidate, Civil engineering department. Shahroud Branch, Islamic azad university, Shahroud, Iran
2 Assistant Professor, Civil engineering department. Shahroud Branch, Islamic azad university, Shahroud, Iran
3 PhD, Department of civil and environmental engineering (Concrete and Building Materials Laboratory), Amirkabir university of technology, Tehran. Iran.
چکیده English

Concrete is one of the most widely used materials in the current century. At high temperatures, due to high thermal stresses and low tensile strength, this material suffers from problems such as cracking, crumbling, or disintegration. In this research, concrete samples have been reinforced using steel and polypropylene fibers and subjected to different temperatures from 25 degrees to 800 °C, and compressive and tensile strength tests have been performed on the samples. In order to better examine the results, a concrete sample containing lightweight aggregate was also prepared and tested along with other samples. The test results showed that with the addition of steel and polypropylene fibers, the compressive strength up to the temperature of 200 °C is higher or similar to the control sample. Also, the tensile strength test results showed that samples containing steel fibers had the highest tensile strength at all temperatures. The results of the compressive and tensile strength test also displayed that at temperatures of 600 °C and above, the lightweight concrete sample has a higher or similar strength to the control sample. Polypropylene fibers start to melt at 400 °C, which has caused a drop in compressive and tensile strength in samples containing this type of fibers at temperatures above 400 °C.

کلیدواژه‌ها English

Mechanical properties
high temperatures
light-weight concrete
fiber reinforced concrete
steel fibers
Polypropylene fibers
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  • تاریخ دریافت 01 آبان 1402
  • تاریخ بازنگری 08 دی 1402
  • تاریخ پذیرش 18 دی 1402