مطالعه آزمایشگاهی بهبود رفتار خمشی تیرهای بتن مسلح بازیافتی با استفاده از الیاف مجزا و هیبریدی فولادی و کورتا

نوع مقاله : مقاله پژوهشی

نویسندگان

1 کارشناس ارشد مهندسی سازه، دانشکده فنی و مهندسی، دانشگاه لرستان

2 گروه عمران، دانشکده فنی و مهندسی، دانشگاه لرستان، خرم آباد، ایران

3 گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه لرستان، خرم آباد، ایران

چکیده

با توجه به اینکه در یکی دو دهه اخیر، تحقیقات در خصوص بتن‌های الیافی گسترش خوبی داشته و در حال حاضر به عنوان یکی از محورهای تحقیقاتی مهم در تکنولوژی بتن به حساب می‌آید. همچنین استفاده از بتن‌های با سنگدانه بازیافتی که تحقیقات در مورد آنها در حال افزایش است. به‌دلیل استفاده از سنگدانه بازیافتی، برخی مشخصات مکانیکی آنها نسبت به بتن با سنگدانه طبیعی ضعیف‌تر بوده و بنابراین استفاده از الیاف در ساخت بتن باعث تقویت برخی مشخصات مکانیکی بتن شده و ضعف‌های بتن در این مشخصات مکانیکی تا حدود زیادی مرتفع نموده است. در تحقیق حاضر با استفاده از الیاف مختلف از نظر جنس و مصالح و به‌صورت مجزا و ترکیبی در بتن‌های با سنگدانه بازیافتی مورد استفاده قرار گرفته و پارامترهای رفتار خمشی این تیرهای ساخته شده با آنها مورد بررسی و مقایسه قرار گرفته است. برای این منظور از دو نوع الیاف فولادی و کورتا به‌صورت مجزا و ترکیبی در ساخت تیرهایی با ابعاد واقعی (سه نمونه تیر) مورد استفاده قرار گرفت. همچنین برای مقایسه نتایج، دو نمونه تیر بدون الیاف و با سنگدانه طبیعی و مصنوعی ساخته شده و نتایج تیرهای الیافی با سنگدانه بازیافتی با آنها مورد مقایسه قرار گرفت. آزمایش مقاومت خمشی چهار نقطه‌ای بر روی نمونه‌ها انجام شد. مود شکست و پارامترهای رفتار خمشی تیرهای با سنگدانه‌های بازیافتی مورد بررسی قرار گرفت. نتایج نشان داد که افزودن الیاف ترکیبی نسبت به الیاف مجزا تأثیر بسیار بهتری در بهبود رفتار خمشی تیرهای بتن مسلح داشته و ضعف استفاده از سنگدانه‌های بازیافتی را در رفتار خمشی تیر برطرف می‌کند. 

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Experimental Study to Improve the Flexural Behavior of Recycled Reinforced Concrete Beams Using Separate and Hybrid Fibers of Steel and Kortta

نویسندگان [English]

  • Abas Eskandari 1
  • Fereydoon Omidinasab 2
  • Ahmad Dalvand 3
1 Master of Structural Engineering, Faculty of Engineering, Lorestan University
2 Department of Civil Engineering, Faculty of Engineering, Lorestan University, Khorramabad, Iran
3 Department of Engineering, Lorestan University, Khorramabad, Iran
چکیده [English]

Due to the fact that concrete is one of the most widely used construction materials and concrete has low ductility, tensile strength and flexural strength along with good compressive strength. To this end, in recent years, by adding fibers to concrete and making reinforced fiber concrete, these weaknesses have been greatly improved. In this study, four samples of reinforced concrete beams were made with recycled aggregate and one sample of beams was made with natural aggregate and in real scale with dimensions of 150×50×20 centimeters. Separate and hybrid types of steel and Kortta fibers were used in the manufacture of beams. In three beam specimens, steel and Kortta fibers were used separately and hybrids and no fibers were used in the beam specimen. In fiber beams and one of the beams without fibers, recycled aggregate was used in their concrete and in one of the fabricated beams, neither fiber nor recycled aggregate was used and it was used as a reference sample in the performed studies. Four-point flexural strength test was performed on the samples. Fracture mode, flexural behavior parameters of beams made with recycled aggregates were investigated. The results showed that the addition of hybrid fibers has a very positive effect on improving the flexural behavior of reinforced concrete beams and eliminates the weakness of recycled aggregates in flexural behavior compared to beams made with natural aggregates.

کلیدواژه‌ها [English]

  • Separate fibers
  • Hybrid fibers
  • Flexural behavior
  • Reinforced concrete beam
  • Recycled aggregate

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