بررسی آزمایشگاهی رفتار خمشی و شکل‌پذیری تیرهای دو دهانه بتن مسلح با جایگزینی کامپوزیت سیمانی الیافی توانمند (HPFRCC)

نوع مقاله : علمی - پژوهشی

نویسندگان

1 عمران ، عمران،دانشگاه سمنان، شهر سمنان ، ایران

2 دانشیار، دانشکده مهندسی عمران، دانشگاه سمنان، سمنان، ایران

3 استاد، دانشکده مهندسی عمران، دانشگاه سمنان، سمنان، ایران

چکیده

ضعف بتن ترد شکنی و عدم شکل پذیری می باشد و استفاده از الیاف فولادی یک راه حل مناسب برای غلبه بر این ضعف است. رفتار سخت شوندگی کرنش تحت کشش که با سایر کامپوزیت های سیمانی و بتنی متفاوت است، از HPFRCC یک مصالح توانمند با قابلیت جذب انرژی بالا و قابلیت ترک خوردگی های زیاد قبل از شکست ساخته است. بنابراین کاربرد سازه ای این مواد کامپوزیتی در اعضای سازه ای مانند تیرهای سراسری، برای کنترل ترک و ارتقاء قابلیت شکل پذیری، رو به گسترش است. در این مقاله تاثیر استفاده از کامپوزیت سیمانی الیافی توانمند حاوی 2% الیاف فولادی در رفتار و عملکرد خمشی تیرهای بتن مسلح دو دهانه بررسی گردیده است که دو تیر با بتن معمولی و دوتیر دیگر با بتن HPFRCC بودند که هر کدام با دو نوع متفاوت چیدمان خاموت در ناحیه تکیه گاه میانی و وسط دهانه ساخته شدند. تیرها دارای دو دهانه مساوی به طول 1800میلیمتر بوده و نیروی متمرکز در وسط دهانه و به صورت متقارن و به صورت افزاینده اعمال گردید. نتایج تحقیق نشان داد که استفاده از کامپوزیت سیمانی الیافی توانمند (HPFRCC) با 2% الیاف فولادی در نمونه ها باعث افزایش شکل پذیری، جذب انرژی، و افزایش ظرفیت باربری و بهبود رفتار مناسب ناحیه مفصل پلاستیک تیرهای بتن مسلح دو دهانه سراسری گردید.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Experimental Investigation on Flexural Behaviour and Ductility of Two-Span RC Beams Cast with High Performance Composites HPFRCC

نویسندگان [English]

  • ramin ehsani 1
  • Mohammad Kazem Sharbatdar 2
  • Ali Kheyroddin 3
1 Faculty of Civil Engineering, Semnan University, Semnan, Iran
2 Associate Professor, Civil Engineering Faculty, Semnan University, Semnan, Iran
3 Professor, Faculty of Civil Engineering, Semnan University, Semnan, Iran
چکیده [English]

The particular weaknesses of concrete are brittle fracture and lack of material ductility, so using steel reinforcements and discrete fibres are an attempt to overcome this weakness. Strain hardening behaviour under tensile force has made new material HPFRCC as a high performance material with high energy absorption capability and high cracking ability before failure, Therefore the structural application of this composite material in the structural members such as continuous beams to control cracks and improve ductility has come to the believed border. In this paper, the effect of using HPFRCC containing 2% steel fibres on the flexural performance of four large two-span reinforced concrete beams has experimentally been investigated. Two beams were conventional concrete with two different arrangements of stirrups in the central support area and two other beams were companion but made with full HPFRCC composites, all beams with two equal spans of 1800 mm were loaded under concentrated force applied in the middle of the span symmetrical and incrementally. The results indicated that the use of HPFRCC with 2% steel fibre in the specimens increased the ductility, energy absorption, and bearing capacity, as well as an appropriate re-distributing moment in the plastic area of reinforced concrete continuous beam with two spans.

کلیدواژه‌ها [English]

  • "HPFRCC"
  • "Continuous beam"
  • Flexural behavior"
  • "ductility"
  • "Steel Fibres"
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