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BEHAVIOR OF HYBRID REINFORCED CONCRETE BEAMS COMBINING REACTIVE POWDER CONCRETE AND VARYING YTPES OF LIGHTWEIGHT CONCRETE
سلوك الانثناء للعتبات الخرسانية المسلحة الهجينة المتكونة من خرسانة عالية المقاومة وأنواع مختلفة من الخرسانة خفيفة الوزن

Authors: Yaarub G. Abtan --- Hind T. Jaber
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2016 Volume: 20 Issue: 2 Pages: 204-223
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The main objective of this research was studied the flexure behavior of hybrid reinforced concrete beams combining reactive powder concrete (RPC) and lightweight concrete (LWC). The experimental work consists of casting and testing in flexure 12 simply supported reinforced concrete beams. The dimensions of (12) beams were geometrically similar, having rectangular cross-section, of dimensions (125×200×1600) mm. Lightweight concrete was used in tension layer and reactive powder concrete was used in compression layer for all hybrid concrete beams. The main variables were type of concrete (LWC and RPC), thicknesses of RPC layer (hR =0, 50 and 100) mm, volumetric steel ratios (Vf =1%) in LWC and type of LWC (porecilenite aggregate, polystyrene and sawdust). The results showed that the characteristic strength (first and ultimate loads) was increased when the thickness of RPC layer was increased; this increased percentage were (7-100) % and (32-133) % respectively for first cracking loads and ultimate loads. In addition to that, these parameters were decreased the values of deflection from (1-17) %. However that it can be seen from the experimental results, the concrete with steel fiber and porecilenite had more effective than the concrete with other types of aggregate (sawdust and polystyrene). Also the concrete with porecilenite type reflected more number of cracks than sawdust and polystyrene, respectively. All beams failed by flexure mode without any shear cracks which achieved by yielding of tensile steel in the tension zone. Also, for all hybrid beams, the slip was absent between the concrete layers.

يستعرض البحث الحالي دراسة عملية لسلوك الانثناء للعتبات الهجينة المتكونة من خرسانة عالية المقاومه و الخرسانة خفيفة الوزن. يتضمن العمل المختبري صب وفحص أثنتا عشر عتبه خرسانية مسلحة بسيطة الاسناد ((simply supported. كانت أبعاد (12) عتبه متماثلة هندسيا، ذو مقطع عرضي مستطيل ،وبأبعاد mm (125×200×1600). أما المتغيرات الرئيسة لهذا البحث فهي نوع حيث تم استخدام خرسانة المساحيق الفعالة والخرسانه خفيفة الوزن,سمك طبقة خرسانة المساحيق الفعالة (hR =0, 50 and 100) mm,تم استخدام نسبه (%1) لألياف الحديد في طبقه الخرسانه الخفيفة الوزن ونوع خرسانه خفيفة الوزن (حجر البورسلنايت , كرات الفلين ونشارة الخشب ). أظهرت النتائج المختبرية أن خصائص المقاومة ( الشقوق الأولى و الاحمال القصوى ) تزداد عند زياده ارتفاع طبقة خرسانة المساحيق الفعالة , هذه الزيادة المؤية كانت تتراوح مابين (7-100)% و (32-133) بالتتابع لأحمال الشقوق الاولى والأحمال القصوى. بالأضافه الى ذالك هذه المتغيرات نقصت من قيمة الهطول بمقدار (1-17)%. بينما تمت الملاحظة من خلال النتائج المختبرية أن الخرسانة مع الياف الحديد و البورسلنايت تكون أكثر فعالية من خرسانة الأنواع الأخرى من الركام ( كرات الفلين ونشارة الخشب). كذلك الخرسانة المكونة من البورسلنايت تظهر أكثر تأثيرا في عدد الشقوق من الفلين ونشارة الخشب تتابعا. كل العتبات قد فشلت بالأنثناء بدون اضهار أي شقوق قص أي حديد التسليح الحد الأقصى. كذلك لكل العتبات الهجينة, لم يظهر الانزلاق بين طبقات الخرسانة.

Keywords

RPC --- LWC --- Hybrid beam --- Steel Fiber --- Flexure.


Article
Flexural BEHAVIOR OF HYBRID REINFORCED CONCRETE BEAMS COMBINING ULTRA HIGH STRENGTH CONCRETE AND PORECILENITE AGGREGATE LIGHTWEIGHT CONCRETE

Authors: Yaarub G. Abtan --- Hind T. Jaber
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 6 Pages: 178-193
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The main objective of this research was studied the flexure behavior of hybrid reinforced concrete beams combining reactive powder concrete (RPC) and lightweight concrete (LWC). The experimental work consists of casting and testing in flexure seven simply supported reinforced concrete beams. The dimensions of (7) beams were geometrically similar, having rectangular cross-section, of dimensions (125×200×1600) mm. Lightweight concrete was used in tension layer and reactive powder concrete was used in compression layer for all hybrid concrete beams. The main variables were; type of concrete (LWC and RPC), thicknesses of RPC layer (hR =0, 50, 100 and 200) mm and longitudinal reinforcement ratios (ρ= 0.0033 and 0.0227). The type of LWC used in the experimental work was porecilenite aggregate. The results showed that the characteristic strength (first and ultimate loads) was increased when the thickness of RPC layer was increased. In addition to that, these parameters were decreased the values of deflection. All beams failed by flexure mode without any shear cracks which achieved by yielding of tensile steel in the tension zone. Also, for all hybrid beams, the slip was absent between the concrete layers. Finally, the reinforcement ratio (ρ) had more effective factor of all parameter used to increase the stiffness value of the beams which increased the characteristic strength and reduced the deflection values.

Keywords

RPC --- LWC --- Hybrid beam --- Steel Fiber --- Flexure

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