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Article
Shear Strength of Concrete Deep Beam Subjected to Uniformly Distributed Load

Authors: Eyad K. Sayhood --- Ali S. Resheq --- Ayad J. Habeeb
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2018 Volume: 36 Issue: 2 Part (A) Engineering Pages: 125-135
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

In this paper, result of tests on 20 simply supported concrete deep beams are presented. All tested beams have dimensions of (150 x 400 x 1100) mm and tested under (1, 2, 4 and 8) point loads. The considered parameters are shear span to effective depth ratio (a/d), concrete compressive strength (fʹc) and longitudinal reinforcement ratio (ρw).The influence of these parameters on cracking and ultimate load, load versus deflection response and concrete strain are investigated.The results showed that the decrease in the (a/d) ratio from 1.373 to 0.412 leads to a decrease in cracking and ultimate shear strengths by average ratios of 40 % and 57 % respectively, while increasing (fʹc) and (ρw) leads to the increase in the cracking and ultimate shear strengths. The load-deflection response is significantly affected by the (a/d) ratio and becomes appreciably nonlinear as the (a/d) ratio increases, while it is slightly affected by the compressive strength of concrete (fʹc) and steel ratio (ρw). Strain distribution through the depth at mid span is nonlinear even in elastic stage. At the same load level, strain distribution increases as (a/d) increases and decreases as (fʹc) and (ρw) increase. The analytical work has been made on the 20 deep beams plus 62 from literature using the regression analysis. Proposed equation was compared with four equations available in literature and gave less average and coefficient of variation equal to1.04 and 16.98% respectively.


Article
PUNCHING SHEAR STRENGTHS OF HYBRID REINFORCED CONCRETE FLAT PLATE SLABS

Authors: Suha Rasheed Abass --- Haitham Jameel Abd
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 4 Pages: 101-115
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

This study is conducted to test experimentally the punching shear of reinforced concrete flat plate slabs made with hybrid concrete (two types of concrete in two layers in specimens. Twelve test slab with ( 450×450×50 ) mm dimension The tested slabs have been. divided into four groups, each of which consisted of three slab specimens identical in size and shape but different in concrete type and steel bar reinforcement. All slabs are simply supported along the all edges and subjected to single point load applied at the center of gravity of each slab.Experimental results show that the use of hybrid concrete and high strength concrete improves the punching shear resistance and allows higher forces to be transferred through the slab-column connection. For slab specimen which fully cast using high strength concrete, the ultimate shear capacity increased by (40%) in comparison with the normal concrete slabs. While, for slab specimens cast using with hybrid concrete the ultimate shear capacity increased by (5%-45%) in comparison with the normal concrete slabs.This experimental results revealed that the ultimate load capacity increase with the addition of super plasticizers to the mix of concrete.


Article
EFFECT OF STEEL FIBERS RATIO ON THE STRUCTURAL BEHAVIOR OF DOMES
تأثير نسبة الألياف الفولاذية على السلوك الهيكلي للقباب

Authors: Mohammed Mohammed Rasheed --- Layth Abdulbari Al-Jaberi --- Nadiyah Kherallah Abd
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 5 Pages: 118-129
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The main objective of the current paper is to investigate the effects of the ratio of steel fibers on structural behavior of reinforced concrete hemispherical domes. Three reinforced concrete domes were experimentally implemented, two of them made fully of reactive powder concrete and the last one made of ferrocement concrete. All specimens have 800 mm diameter, 400 mm height and 20 mm thickness, and they reinforced with welded wire meshes. The experimental program included casting and testing the domes, by applied a single point load at the center of dome, until the failure is happened. The first cracking load, ultimate load, load deflection curves, and crack pattern for all tested domes were included in this study. In general, the effects of concrete type and the ratio of steel fiber are obviously important on the behavior and ultimate strength of the domes.


Article
Some Properties of High Strength Sustainable Concrete Containing Glass Powder Waste

Authors: Wasan I. Khalil --- Nazar F. Al-Obeidy
Journal: DIYALA JOURNAL OF ENGINEERING SCIENCES مجلة ديالى للعلوم الهندسية ISSN: 19998716/26166909 Year: 2018 Volume: 11 Issue: 2 Pages: 24-32
Publisher: Diyala University جامعة ديالى

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Abstract

This investigation includes the use of glass wastes after recycling to produce high strength sustainable concrete. The glass waste used is prepared to be a natural Pozzolan class (N) according to ASTM C618 with fineness of about 7340 cm2/gm. Many concrete mixes with different percentages of glass waste powder as a partial replacement by weight of cement (10%, 15%, 20%, 25%, and 30%) were prepared to study some properties of concrete (compressive strength, splitting tensile strength, flexural strength, and modulus of elasticity at 60 day age). The test results indicate that the mechanical properties of concrete are improved with the increase of glass waste powder up to 15%, and then decreased. The maximum percentages of increase for compressive, splitting tensile, flexural strengths, and modulus of elasticity are 13.29%, 36.27%, 34.68%, and 8.2% respectively relative to the reference for concrete specimens containing 15% glass waste powder as a replacement by weight of cement.Corrosion inhibition of low carbon steel, stainless steel types 316 and 304 in hydrochloric acid by potassium iodide was investigated at different temperatures using weight loss and polarization electrochemical techniques


Article
Study The Effect of Micro CaCO3 and SiO2 and their Mixture on Properties of High Strength Concrete

Authors: Ahmed M. Al Ghaban --- Aseel B. Al Zubaidi --- Zahraa F. Jawad
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2018 Volume: 36 Issue: 10 Part (A) Engineering Pages: 1027-1033
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

This paper investigated the effect of incorporating two types of micro particles micro CaCO3 and micro SiO2 on mechanical properties and durability of concrete. Micro materials were added in four different dosages of 1%, 2%, 3% and 4% by weight as partial replacement of cement in concrete mixture. Mechanical properties of hardened concrete (compressive strength, flexural strength and split tensile strength) have been done after 28 days of water curing. In addition, water absorption test was carrying out for obtaining the durability properties of concrete specimen. Binary combination of micro CaCO3 + micro SiO2 were also studied the combined effect of the micro particles. Micro-structural characteristic of modified concrete was done through the scanning electron microscope. The results showed that incorporation of micro CaCO3 and micro SiO2 particles lead to increase the packing and enhance the mechanical properties and durability of concrete. A significant performance was observed in case of micro silica addition to the concrete in comparing with other micro particles.


Article
EFFECT OF ADDITION OF CHOPPED CARBON FIBER ON THE BEHAVIOR OF REINFORCED CONCRETE BEAMS WITH VARIABLE (SHEAR DISTANCE TO EFFECTIVE DEPTH ) RATIOS.
تأثير اضافة الياف الكربون المقطعه على سلوك الكمرات الخرسانية المسلحة بنسب (مسافة قص الى عمق فعال) مختلفة

Authors: Ahmed Sahib Diab AL-Ridha --- Esraa Khudhair Mohsin Abuzaid --- Ali Abdul-Razzaq Abbood
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 1 Pages: 137-148
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The main objective of this work is to evaluate strength and behavior of reinforced concrete beams reinforced with discrete carbon fiber. Six beams were cast and tested up to failure under two concentrated static loads. Four beams were strengthened with discrete carbon fiber (two of them reinforced with carbon fiber of length 12mm and the other two with 6mm carbon fiber). The remaining two were casted without using carbon fiber as a reference beams. Load-deflection response of all the beams was evaluated. The effect of shear span to effective depth ratio and carbon fiber pecies length on the behavior of beams was studied. The results revealed a good improvement provided b the usage of carbon fiber as compared with the references beams (without carbon fiber). The results also show that. The use of carbon fiber lead to a good improvement in the ultimate load value [ (6mm) length carbon fiber increased (Pu) by 18.75% for (a/d = 4/3) and by 20% for (a/d = 4), while the (12mm) length carbon fiber increased (Pu) by 64.06% for (a/d = 4/3) and by 80% for (a/d = 4)].


Article
Development length of Tension Bars in Concrete Beams- Revisited
طول تثبيت قضبان الشد في العتبات الخرسانية المسلحة – دراسة شاملة

Author: Dhiyaa hamoodi Mohammed ضياء حمودي محمد
Journal: Iraqi Journal of Civil Engineering المجلة العراقية للهندسة المدنية ISSN: 19927428 Year: 2018 Volume: 12 Issue: 1 Pages: 26-34
Publisher: University of Anbar جامعة الانبار

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Abstract

Presently development length of tension bars in reinforced concrete beams, in both codes and researches has a very wide range on the influence of major parameters. Namely, the influence of concrete compressive strength f́c affects the development length of beams by varying power values: 1/2, and 1/3. It is well known that the development length of beams is essentially based on empirical or semi empirical formulae. A total of 254 NSC and HSC tested beams available from the literature are studied in this work. These includes 154 beams without transverse reinforcement and 100 with transverse reinforcement and having a different compressive strength ranged from (16.4 – 98) MPa. The best available design method obtained from the literature leads to 43.31% increase in the coefficients of variation COV compared to the proposed design method in this work, which is essentially whose COV of 14.06%.

ان طول تثبيت قضبان الشد في العتبات الخرسانية المسلحة في كل من المدونات والبحوث يتأثر وبشكل كبير بالاعتماد على مجموعة من المتغيرات الرئيسية. وأهم هذه المتغيرات الرئيسية هو مقاومة انضغاط الخرسانة (f́c) حيث تاثيره يختلف باختلاف اس المتغير (power values) والذي يتراوح من 2/1 الى 3/1. كذلك من المعروف جدا هو ان حساب طول تثبيت قضبان الشد في العتبات الخرسانية تعتمد على المعادلات التجريبية او شبه التجريبية. تم في هذا البحث جمع ودراسة بيانات عملية مع تفاصيلها لمجموعة من العتبات الخرسانية المسلحة والبالغ عددها 254 عتبة من بحوث سابقة. حيث شملت هذه المجموعة على دراسة 154 عتبة خرسانية غير مسلحة بحديد التسليح العرضي بالاضافة الى دراسة 100 عتبة خرسانية مسلحة بحديد التسليح العرضي وذات مقاومات انضغاط خرسانية (f́c) مختلفة تتراوح من (98-16.4) ميغا باسكال. تم ايجاد معادلة لحساب طول تثبيت قضبان الشد في العتبات الخرسانية المسلحة ذات معامل ارتداد (COV) بقيمة (14.06) والذي هو اقل ب (43.31%) من افضل معامل ارتداد لمعادلات المدونات ومعادلات الباحثين السابقين.


Article
Experimental Investigation of Short Square Normal and Hybrid Fiber Reactive Powder Concrete Columns Subjected to Chloride Solution Attack
التصرف العملي للأعمدة الخرسانية القصيرة مربعة المقطع ذات الخرسانة العادية والمساحيق الفعاله المسلحة بالياف هجينة والمعرضة لهجوم محلول الكلورايد

Authors: Mohammed Mosleh Salman محمد مصلح سلمان --- . Husain Khalaf Jarallah حسين خلف جارالله --- Raed Satar Al-Behadili رائد ستار البهادلي
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2018 Volume: 24 Issue: 7 Pages: 75-94
Publisher: Baghdad University جامعة بغداد

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Abstract

In this research, the structural behavior of reinforced concrete columns made of normal and hybrid reactive powder concrete (hybrid by steel and polypropylene fibers) subjected to chloride salts with concentration was 8341.6 mg/l. The study consists of two parts, the first one is experimental study and the second one is theoretical analysis. Three main variables were adopted in the experimental program; concrete type, curing type and loading arrangement. Twenty (120x120x1200) mm columns were cast and tested depending on these variables. The samples were reinforced using two different bars; Ø8 for ties and Ø12 with minimum longitudinal reinforcement (0.01Ag). The specimens were divided into two main groups based on curing type: The first group consists of casting and testing of ten columns that cured in tap water for 28 days with two types of concrete (normal and hybrid), five columns for each type. While the second group consists of ten columns that direct cured and fully immersed in chloride water (8341.6 mg/l) 6 months with two types of concrete (normal and hybrid), five columns for each type. The specimens were tested under three types of loading, the first one is axial load, the second one is eccentric load with three different eccentricities (50,100 and 150) mm and where (e/h) are (0.42, 0.83 and 1.25) respectively from the center of column while the third type of loading is tested the specimens as beam.The experimental results showed an increase in ultimate load capacity and higher chlorides resisting for hybrid reactive powder concrete in comparison with normal concrete in both types of curing (tap and chloride water) through studying strain profile. Interaction diagram charts were obtained from different types of loading for each specimen. These charts showed high values for hybrid reactive powder concrete in comparison with normal concrete.

في هذا البحث تم دراسة التصرف الانشائي للاعمدة الخرسانية والمعرضة للاملاح الكلوريدية و (بتركيز 8341.6 ملغملتر) في نوعين من الخرسانة العادية وذات المساحيق الفعاله والمهجنة بالالياف ((steel and polypropylene fibers. تم اجراء ( جانبين في البحث الاول الجانب العملي والثاني الجانب النظري. يتضمن الجانب العملي ثلاث متغيرات هي نوع الخرسانة ونوع المعالجة ونوع التحميل, حيث تم صب وفحص 20 عمود خرساني بابعاد (120 × 120) ملم وبارتفاع 1200 ملم واستخدام نوعين من الاقطار لحديد التسليح Ø8 للاطواق المقاومة للقص و Ø12 التسليح الطولي وبنسبة 1%, تم تجزئة الجانب العملي الى جزئين: الجزء الاول وهو صب 10 اعمدة ومعالجتها في المياه العادية لمدة 28 يوم بنوعين من الخرسانة العادية والمهجنة 5 اعمدة لكل نوع خرسانة اما الجزء الثاني هو صب 10 اعمدة ومعالجتها بالمياه الكلوريدية و (بتركيز 8341.6 ملغملتر) وغمرها كليا لمدة 6 اشهر وايضا بنوعين من الخرسانة ولكل نوع 5 اعمدة.في الفحص تم تسليط ثلاث انواع من الحمل وهي الحمل المحوري واللامحوري وهي (50, 100, 150) ملم ونسبة ( (e/h0.42 , 0.83 و 1.25 ) من سنتر العمود والحمل الاخير هو فحص النموذج كعتبة.اظهرت النتائج العملية زيادة في الحمل والمقاومة في كلا المعالجة العادية والكلوريدية للخرسانة المهجنة مقارنة بالخرسانة العادية من خلال الحصول على interaction diagram chart, strain profile من خلال اختلاف نوع الحمل لكل نموذج حيث اظهرت النتائج الارقام العالية لرسم ال chart للخرسانة المهجنة مقارنة بالعادية.


Article
Properties of Epoxy-Asphalt Pavement Mixture for Bridge Decks
خصائص خرسانة التبلیط نوع الإسفلت ایبوكسي لرصفة الجسر

Authors: Amjad H. Albayati أمجد حمد البیاتي --- Esraa T. Al-Azawee اسراء ثامر العزاوي
Journal: AL-NAHRAIN JOURNAL FOR ENGINEERING SCIENCES مجلة النهرين للعلوم الهندسية ISSN: 25219154 / eISSN 25219162 Year: 2018 Volume: 21 Issue: 1 Pages: 20-27
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

Improving the ability of asphalt pavement to survive the heavily repeated axle loads and weathering challenges in Iraq has been the subject of research for many years. The critical need for such data in the design and construction of more durable flexible pavement in bridge deck material is paramount. One of new possible steps is the epoxy asphalt concrete, which is classified as a superior asphalt concrete in roads and greatly imparts the level of design and construction. This paper describes a study on 40-50 penetration graded asphalt cement mixed with epoxy to produce asphalt concrete mixtures. The tests carried out are the Marshall properties, permanent deformation, flexural fatigue cracking and moisture damage. Epoxy asphalt mixes performed better on resistance to fatigue and permanent deformation. They also performed significantly better on low-temperature properties and resistance to moisture damage. The addition of 30 percent of epoxy (by weight of asphalt cement) resulted in increase of Marshall stability by 39.8 percent, improve the tensile strength ratio by 22.9 percent, lowering both the rate of permanent deformation by 26.8 percent and the fatigue accumulation coefficient by 53.5 percent, in comparison with control HMA. Based on the above findings, it is recommended to use epoxy asphalt mixes as an optimal material for paving bridges deck in Iraq since it showed good prospects for this application due to the valuable performance and durability improvement.


Article
ENGINEERING PROPERTIES OF SUSTAINABLE SELF- COMPACTING CONCRETE WITH CLAY BRICKS WASTE AGGREGATE

Authors: Thaer A. Al-Daebal --- Wasan I. Khalil
Journal: KUFA JOURNAL OF ENGINEERING مجلة الكوفة الهندسية ISSN: 25230018 Year: 2018 Volume: 9 Issue: 3 Pages: 223-239
Publisher: University of Kufa جامعة الكوفة

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Abstract

The present study covers the use of different percentages (25, 50, 75 and 100%) of clay bricks waste as replacement by volume of coarse natural aggregates to produce sustainable self- compacted concrete (SCC). All mixes used containing 10% silica fume as a replacement by cement weight. The properties of SCC studied were, workability, fresh density, dry density, water absorption, compressive strength, splitting tensile strength, flexural strength, modules of elasticity and thermal conductivity. The results show that the flow ability, filing ability, and passing ability of self -compacted concrete through steel reinforcement are decrease with the increase of clay brick waste content. In addition, the segregation resistance decreases with the increase of clay brick waste content of SCC. The use of clay brick waste aggregate causes reduction in density, compressive strength, splitting tensile strength, flexural strength, modules of elasticity and thermal conductivity of SCC. The percentage reduction increases with the increase of clay bricks waste content in self-compacted concrete.

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