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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
STUDY THE EFFECT OF USING LOCAL MATERIALS AS REFRACTORY BONDING MORTAR IN IRAQI
دراسة تأثير استخدام المواد المحلية كمونة رابطة حرارية

Authors: Katreen E. Al Hwaidy كاترين عيسى عزيز --- Shatha S. Hassan شذى صادق حسن --- Osama A. Eedan اسامة عبد الامير عيدان
Journal: KUFA JOURNAL OF ENGINEERING مجلة الكوفة الهندسية ISSN: 25230018 Year: 2018 Volume: 9 Issue: 1 Pages: 143-157
Publisher: University of Kufa جامعة الكوفة

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Abstract

In this research, Iraqi bauxite was used as raw material, after preparation the producing a grog. The mix proportion was applied, (96:4), (93:7) and (90:10) as (bauxite grog: kaolin binding ), and the sodium silicate solution as adhesive material 5% by weight of the mix.The burning temperatures for specimens' producing were 1450ᵒC. The physical investigation was carried such as (bulk density, specific gravity, apparent of porosity and water absorption). While the mechanical tests (compressive, bonding) strength, durability investigations such as (thermal shrinkage, reheating expansion and thermal shock). It was found the third group recorded the highest compression and bonding strength and thermal shock resistance and the best physical properties after burning at 1450 ºC, with mix proportion (90: 10).

في هذا البحث تم استخدام اطيان البوكسايت العراقي كمادة اولية بعد تحضيرها لانتاج الركام الحراري (كروك). تم ) ( ركام البوكسايت الحراري: المادة الرابطة الكاؤولين) وكذلك محلول 10 :90) و (7 :93( ,)4 :96تطبيق ثلاث نسب ( )1450% من وزن العينة لكل خلطة . كانت درجة حرارة حرق العينات تصل الى (5سليكات الصوديوم كمادة لاصقة بنسبة درجة مئوية . تم اجراءالتحريات الفيزيائية مثل ( الكثافة الظاهرية , الوزن النوعي, المسامية الظاهرية, و امتصاص الماء) . بينما الفحوصات الميكانيكية التي اجريت على العينات هي ( مقاومة الانضغاط , مقاومة الربط) وكذلك فحوصات الديمومة مثل ) اعلى مقاومة 10:90 (الانكماش الحراري, التمدد بعد اعادة الحرق والصدمة الحرارية ) حيث سجلت الخلطة الثالثة ( م.º 1450للانضغاط والربط والصدمة الحرارية وافضل خواص فيزيائية بعد الحرق بدرجة.


Article
USING LOCAL IRAQI MATERIALS IN PRODUCTION OF REFRACTORY BONDING MORTAR

Authors: Katreen E. Al Hwaidy --- Osama A. Eedan --- Shatha S. Hassan
Journal: KUFA JOURNAL OF ENGINEERING مجلة الكوفة الهندسية ISSN: 25230018 Year: 2018 Volume: 9 Issue: 2 Pages: 91-102
Publisher: University of Kufa جامعة الكوفة

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Abstract

The Iraqi kaolin clay was used as a raw material in this research. three mix proportion was applied, (96:4), (93:7) and (90:10) as (kaolin grog: kaolin binding ). The specimens of mortar were burning at 1500ᵒC, after producing a refractory aggregate (grog) by preparation process mixing with sodium silicate solution as adhesive material with 5% by weight of the mix. The mechanical tests were carried (compressive and bonding) strength, durability investigations (thermal shrinkage, and reheating expansion), and the physical investigation was carried (bulk density, specific gravity, apparent porosity and water absorption). It was found the first mix (96:4) recorded the highest compressive strength befor burning and bonding after burning, and the best physical properties after burning at 1500 ºC, with mix proportion (96: 4), while the highest compressive strength after burning were the mix three (90: 10).


Article
Capability of Pocket Penetrometer to Evaluate Unconfined Compressive Strength of Baghdad Clayey Soil
مطابقة قراءة اداة اختراق التربة لحساب مقاومة الانضغاط غیر المحصور لنموذج تربة طینیة غرینیة من محافظة بغداد

Author: Azhar Sadiq Yasun أزھر صادق یاسین
Journal: AL-NAHRAIN JOURNAL FOR ENGINEERING SCIENCES مجلة النهرين للعلوم الهندسية ISSN: 25219154 / eISSN 25219162 Year: 2018 Volume: 21 Issue: 1 Pages: 66-73
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

Unconfined compressive strength represents an important parameter for soil investigation report test results because the values of cohesion and allowable bearing capacity can directly obtained from the relevant test especially if the clayey soil layers are found at sufficient enough depth above water table level.This paper deals with simple comparison (based on (31) soil samples) between unconfined compressive strength (qu) obtained by using the pocket soil penetrometer tool and the unconfined compressive strength using the conventional test for the same sample penetrated by the pocket penetrometer with different soil moisture contents. Two triaxial specimens, sample type-1- with dimensions 38 X 79mm and type-2- with dimensions 33 X 79mm(diam. X height)) prepared in the libratory.It was found that the results refers that soil pocket penetrometer readings are closed enough to the results that obtained from the unconfined compression test result with certain conditions.The average percentage of difference between penetrometer readings and unconfined compression test result values was (1.103%) for sample type-1- and (1.53%) for sample type -2-.The maximum moisture content for all tests samples was (27.3%) and the minimum was (14.7%) while the average moisture content was(20.9%).

الخلاصةان مقاومة الانضغاط غیر المحصور تمثل عاملا مھما في نتائج تقریر تحریات التربة حیث یمكن حساب قوة تماسك التربة ومقاومةالانضغاط المسموحة مباشرة من الفحص اذا كانت الترب الطینیة ضمن عمق مناسب فوق منسوب المیاه السطحیة.یتناول البحث مقارنة أولیة لنتائج فحوص ( 31 ) نموذج تربة تم فحصھا باستخدام اداة اختراق التربة وفحص الانضغاط غیر المحصور 79 ملم) * التقلیدي لنفس النموذج بمحتوى رطوبة فعلي متغیر، وقد تم استخدام نموذجین قیاسیین لفحص الانضغاط ثلاثي المحاور بأبعاد ( 33 .( 79 ملم) لنموذج نوع ( 1 * لنموذج نوع ( 2) و( 38وجد بعد مقارنة النتائج المتحققة لمقاومة الانضغاط غیر المحصورة بین الطریقتین ان مقدار النسبة المئویة للفرق بین القرائتین كان .( %1.53 ) للنموذج رقم ( 2) و( 1.103 %) للنموذج رقم ( 1 )ان مراقبة نتائج محتوى الرطوبة الفعلي المسجل بینت ان القیمة العظمى لمحتوى الرطوبة كانت ( 27.3 %) فیما كان مقدار أدنى محتوى .(% رطوبة فعلي( 14.7 %) فیما كان معدل محتوى الرطوبة الفعلي لكل النماذج ( 20.9 بالاستناد الى الى نتائج الانضغاط الغیر محصور المسجلة فأن ھناك مقبولیة لاستخدام اداة اختراق التربة الموقعیة نظرا لتقارب نتائجھا المسجلة مع قیم فحص الانضغاط الغیر محصور التقلیدي للترب الطینیة وفق شروط یوضحھا البحث.


Article
EFFECT OF HYDROSTATIC WATER PRESSURE ON PERFORMANCE OF SELF-COMPACTING CONCRETE PLACED UNDERWATER

Authors: Ali T. Jasim --- Maryam A. Ali
Journal: KUFA JOURNAL OF ENGINEERING مجلة الكوفة الهندسية ISSN: 25230018 Year: 2018 Volume: 9 Issue: 3 Pages: 145-164
Publisher: University of Kufa جامعة الكوفة

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Abstract

This study has focused on investigation of effect of hydrostatic pressure on the properties of underwater self-compacting concrete. In this research, 30 mixes of self-compacting concrete have been prepared with six groups. The first three groups contain AWA (Anti Washot Admixture), while the second groups made without AWA. The main parameters explored in this research were: silica fume, limestone powder and rice husk ash as a cement replacement content with 0% and 1% anti washout admixture and different water depth (10 ,20, 30 ,40 and 50 m). Washout loss was found by using either the CRD C61 test method or a newly developed device for simulation of increased hydrostatic pressure on the concrete/water interface. Good correlations were investigating between the standard washout loss determined according to CRD C61 and simulated threshold water head and corresponding maximum washout loss.


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
Study of the Mechanical Properties of Jute Fiber Reinforced Cement Composites

Author: Lamees S. Faiq
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2018 Volume: 36 Issue: 12 Part (A) Engineering Pages: 1244-1248
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

t-The study results show the use of jute fibers to develop a low costmaterial for wall panels, roofs and other construction board. The study has beeninvestigates the cement mechanical characteristics jute fibers reinforcedconcrete. Different lengths of fibers (2cm) and (4cm) were mixed to act asreinforcement for the concrete samples. The samples with different fiberpercentages (0.5%, 1% and 1.5% by weight of cement) were tested in axialcompression and splitting tensile strength. A total of (42) concrete cube samples(100mm*100mm*100mm) and (42) cylindrical samples (100mm*200mm) wereused in the tests, these include compressive and splitting tensile strength andwere conducted at (7) and (28) days of concrete age. The results showed thatincreasing the fiber content and length leads to a slight decrease (4.3% - 12.3%)in the compressive strength but it improves the splitting tensile strength whichreached best value at the (1% by weight of cement) fiber content and (5cm)length. The increasing of splitting tensile strength was up to (19.4%) from thereference concrete strength


Article
THE BEHAVIOR OF MORTAR AFTER ADDING IRON WASTE

Authors: Besma Mohammed Fahad1 --- Shatha Riyadh Ahmedizat --- Nisreen Sabah Ali
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 2 (Part-4) Pages: 1-12
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The need for exceeding the strength of construction material with low cost material is the aim of this work. Iron waste was used to replace the sand in (10, 20, and 30%) by weight .three particle sizes (75,100,150 µm) were chosen for iron filling to reveal the most effective particle size. The results showed the lowest density were obtained at 100 µm particle size and 30% by weight of iron filling. The best water absorption was obtained at 100 µm particle size and 10% by weight of iron filling. The highest thermal diffusivity was obtained at 100 µm particle size and 20% by weight of iron filling. The best thermal conductivity were obtained at 100 and 150 µm particle size and 30% by weight of iron filling and The best compressive strength were obtained at 75 µm particle size and 20% by weight of iron filling. For all samples containing iron filling better properties were obtained comparing with control sample.


Article
EFFECT OF NANO-ALUMINA ON MICROSTRUCTURE AND MECHANICAL PROPERTIES OF RECYCLED CONCRETE

Authors: Farhad Mohammed Othman --- Alaa Aladdin Abdel-Hamead --- Raeid Kadhium Mohammed
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 2 (Part-1) Pages: 90-103
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

In this paper, the effect of using recycle mortar as fine aggregate replacement and nano Alumina (Al2O3) powder replaced of cement on the concrete microstructure and their effect on the mechanical properties is investigated. The nano powder was used as additive to replaced (0.5, and 2. 5 wt %) of cement with recycle fine aggregate(RFA) to replacement (10,and 50 wt%) of natural fine aggregate in concrete mixture. The compressive strength and microstructure analysis tests were carried out on the concrete samples. Microstructure analysis tests were conducted using X-Ray Diffraction(XRD), Scanning Electron Microscopy(SEM), and Atomic Force Microscopy(AFM). Results shows that the nano-oxide and recycle aggregate addition leads to different microstructure of concrete. The high specific surface area of nano-oxide causes reduce calcium hydroxide Ca(OH)2 (CH) crystallite in the cement hydration process and the pores structure of calcium silicate hydrated gel lead to products denser and compacted microstructure, also the roughness of concrete surface was reduces which caused enhancement in the compressive strength with the addition of nano- Al2O3


Article
EXPERIMENTAL STUDY ON PROPERTIES OF PERVIOUS CONCRETE PAVEMENT COMPRISING SUSTAINABLE MATERIALS

Authors: Nagham Tariq Al-Shafi’i --- Shakir Falih Al-Busaltan2 --- Ali Adnan Abdulwahid
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 2 (Part-5) Pages: 94-107
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The significant of the porous concrete pavement arises from the fact that it has many applications and advantages specially in filtrate the run water on the pavement surface. In addition, porous concrete offers a vital solution for the noise due to wheel to pavement interaction. So, the aim of this research work is to characterize a porous concrete pavement under local materials and conditions, further to make it more sustainable. This process has been done by three stages, namely: control stage, development stage by silica fume and sustainable stage by Reed Fly Ash. While, three testing methods were conducted to characterize the performance of porous concrete in terms of mechanical and volumetric properties. However, within the scope and materials used, the results showed that the optimum ratios for W/C, C/CA, SF/C, RFA/C are 30%, 20%, 20%, and 8%, respectively. Indeed, such ratios have afforded sustainable porous concrete with satisfactory mechanical strength and acceptable volumetric properties.

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