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Article
IMPROVEMENT OF EXPANSIVE SOIL BY USING SILICA FUME
تحسين الترب الانتفاخية بغبار السيلكا

Author: Kawther Y. AL-Soudany كوثر يلي حسين السوداني
Journal: KUFA JOURNAL OF ENGINEERING مجلة الكوفة الهندسية ISSN: 25230018 Year: 2018 Volume: 9 Issue: 1 Pages: 222-239
Publisher: University of Kufa جامعة الكوفة

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Abstract

Expansive soils are characterized by their considerable volumetric deformations representing a serious challenge for the stability of the engineering structures such as foundations. Consequently, the measurements of swelling properties, involving swelling and swell pressure, become extremely important in spite of their determination needs a lot of time with costly particular equipment. Thus, serious researches attempts have been tried to remedy such soils by means of additives such as cement, lime, steel fibers, stone dust, fly ash and silica fume. In this research the study of silica fume has studied to treatment expansion soil, the clay soil was brought from Al-Nahrawan in Baghdad. The soil selected for the present investigation prepared in laboratory by mixing natural soil with different percentages of bentonite (30, 50 and 70% by soil dry weight). The test program included the effect of bentonite on natural soil then study the effect of silica fume (SF) on prepared soil by adding different percentage of silica fume (3, 5, and 7 by weight) to the prepared soils and the influence of these admixtures was observed by comparing their results with those of untreated soils (prepared soils). The results show that both liquid limit and plasticity index decreased with the addition of silica fume, while the plastic limit is increase with its addition. As well as, a decrease in the maximum dry unit weight with an increase in the optimum water contents have been obtained with increasing the percentage of addition of the silica fume. It is also observed an improvement in the free swell, swelling pressure by using silica fume. It can be concluded that the silica fume stabilization may be used as a successful way for the treatment of expansive clay.

ان الترب الانتفاخية تكون معرضة الى تشوهات حجمية كبيرة لذلك تشكل تهديدا على استقرارية المنشآت و الاسس. لذلك فان معرفة خصائص الانتفاخ مثل الانتفاخ و ضغط الانتفاخ اصبح ضروريا جدا. على الرغم من ان قياس خصائص الانتفاخ يستهلك وقتا ويتطلب معدات خاصة و باهضة. لذلك تم دراسة معالجة الترب الانتفاخية باستعمال مختلف الاضافات مثل الاسمنت, و الالياف الحديدية, غبار الحجر, الرماد المتطاير, وغبار السيلكا. في هذا البحث تم دراسة اضافة غبار السيلكا الى التربة الانتفاخية لمعالجة نسبة الانتفاخ/ الانكماش حيث تم استعمال %) من وزن 70 ,50 ,30تربة طينية من منطقة النهروان في بغداد وتم مزجها مع نسب مختلفة من مادة البنتونايت ( التربة.ان برنامج الفحوصات المختبرية التي اجريت في هذا البحث تضمن ايضا تأثير البنتونايت على التربة الاصلية ومن 7 ,5 ,3 ) ثم غبار السيلكا على التربة حيث تم اضافتها بنسب مختلفة (% من وزن التربة المحضرة. وقد تم مراقبة تأثير اضافة هذه المادة على التربة بدون وجود اضافة و مع وجود الاضاف ومقارنة النتائج. وبينت النتائج ان اضافة غبار السيلكا الى الترب الانتفاخية تؤثر على حدود القوام حيث يقل حد السيولة ومؤشر اللدونة و يزداد حد اللدونة للترب وبينت النتائج ايضا ان بزيادة نسبة غبار السيلكا في الترب الانتفاخية تقل الكثافة الجافة العظمى و يزداد محتوى الماء المثالي. اضافة الى ذلك بينت النتائج الى ان الانتفاخ وضغط الانتفاخ للترب تتحسن بوجود غبار السيلكا في التربة الانتفاخية.


Article
Enforcement of Epoxy with Silica Fume and Carbon Fiber

Author: Amer Hameed Majeed
Journal: Tikrit Journal of Engineering Sciences مجلة تكريت للعلوم الهندسية ISSN: 1813162X 23127589 Year: 2018 Volume: 25 Issue: 1 Pages: 74-77
Publisher: Tikrit University جامعة تكريت

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Abstract

A composite material has been prepared using epoxy resin as a matrix, reinforced with silica fume, carbon fiber, and their hybrid (mixture of silica fume and carbon fiber). Samples were prepared in a fabricated mold with dimensions according to the American Standards for Testing and Materials (ASTM). The additions of silica fume, carbon fiber, and mixture of them were with weight ratios of 0.5, 1, 1.5, 2, 2.5 and 3 wt.%. Properties of this composite material are determined; hardness, compression, and ultrasonic. The results showed that the mechanical properties increases with increasing of silica fume ratio up to 2 wt.%, and for higher than of 2 wt.% they were decrease, whereas the addition of carbon fiber and mixture of carbon fiber with silica fume powder correspondingly enhances the properties up to 2 wt.% and fixed on its values.


Article
Improving the Mechanical Properties of Lightweight Foamed Concrete Using Silica Fume and Steel Fibers

Authors: Suhad M. Abd --- Dhamyaa Ghalib
Journal: AL-NAHRAIN JOURNAL FOR ENGINEERING SCIENCES مجلة النهرين للعلوم الهندسية ISSN: 25219154 / eISSN 25219162 Year: 2018 Volume: 21 Issue: 2 Pages: 300-307
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

Lightweight foamed concrete (LWFC) is characterized as a light in self-weight, self- compacting, self-levelling, and thermal and sound isolation. But it has low strength and low ductility which leads that the application of (LWFC) in the building construction is limited. The flowability of the fresh mix of (LWFC) was evaluated by flow test. While the hardened properties of (LWFC) include, compressive 6 strength, tensile6 splitting6 strength, flexural 6 strength, and 6modulus of 6 elasticity. This 6 study6 focuses6 on the effect of the adding of silica fume and steel fibre on the mechanical properties of (LWFC). Silica fume was added as (5%) and (10%) by the weight of cement and steel fiber (0.2%) and (0.4%) of the total volume of the mix. The density of lightweight foamed concrete was 1800±50kg/�3, and cement to sand ratio was (1:1) with water cement ratio (0.28). The results indicated that adding of silica fume6 and steel 6 fiber 6 have great effect on the mechanical properties and improve them. The addition (10%) of silica fume and (0.4%) by volume of steel fiber was the best ratio that improves the mechanical properties of the lightweight foamed concrete (LWFC). The pozzolanic index of the (5%) and (10%) silica fume was (21.9%) and (74.76%), respectively.


Article
THE EFFECT OF PARTICLE SIZE DISTRIBUTION (PSD) OF RUBBRIZED SELF-COMPACTING CONCRETE (RSCC)

Authors: Nahla Naji Hilal --- Sheelan Mahmoud Hama
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 2 (Part-4) Pages: 13-22
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Three groups of waste scrap: fine rubber, mixed rubber, and tire chips, were used as partial replacement instead of natural fine and coarse aggregate at various level, respectively. The tire chips and three differently graded crumb rubbers (fine crumb rubber, coarse crumb rubber, and mixing crumb rubber) and 5- designated of crumb rubber at 5.0%, 10.0%, 15.0%, 20.0%, and 25.0% replacement levels, were adopted as study parameters. The fresh and hardened properties were investigated. Flexural tensile strength was tested according to ASTMC293 and ASTMC78.The results of this study are affected by size and content of wastes crap tire rubber and the type of testing also effect on the calculated strength. ASTMC293 test method gave higher value than ASTMC78 test method by 30-40%.


Article
FLEXURAL BEHAVIOR OF SLURRY INFILTRATED FIBER CONCRETE (SIFCON) CONTAINING SUPPLEMENTARY CEMENTITIOUSE MATERIALS

Authors: Shakir Ahmed Salih --- Qais Jwad Frayyeh --- Manolia Abed Al-wahab Ali
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 2 (Part-3) Pages: 35-48
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Slurry Infiltrated fiber Concrete (SIFCON) is a relatively new high performance material and can be considered as a special type of Fiber Reinforced Concrete (FRC) with high fiber content. The matrix consists of flowing mortar or cement slurry which must infiltrate properly through the fiber network placed in molds. SIFCON possessing excellent mechanical properties coupled with large ductility and toughness values. SIFCON has found application in area where high ductility and energy absorption are needed especially in seismic-resistant reinforced concrete frames and in structure under abnormal or explosive loads. Other successful applications include pavement overlays, repair of prestressed beams and repair of structural reinforced concrete element.The main aim of this study is to determine the effect of hooked ended steel fiber content and mineral admixture replacement silica fume (SF) on strength and deformation characteristics of SIFCON specimens under flexural loading. Three volume fraction of steel fiber (6, 8.5, and 11) % were used in this investigation .The percentage of SF replacement was (10%), by weight of cement in SIFCON slurry. Both the flexural strength and toughness characteristic were carried out by testing specimens of 100*100*400 mm at the age of 7and 28 days. The results obtained from these tests were compared with those carried out on conventional fiber reinforced mortar (FRM) with 2% fiber content, as control specimens. The test results show superior characteristics of SIFCON ,as compared with normal FRM ,which were affected in positive manner by using cementitiouse materials (SF) as a partial replacement by weight of cement, and with increasing the volume fraction of steel fiber. The flexural strength and toughness value up to (28.08 MPa ) and (159 N.mm),respectively were obtained at age of 28 days.


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.


Article
EFFECT OF ADDING THE PLASTIC WASTE AS FIBERS ON MECHANICAL PROPERTIES OF CONCRETE

Author: Aseel Madallah Mohammed
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 2 (part-6) Pages: 86-95
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

This study investigated the effect of adding the plastic waste resulting from cutting the bottles by hand as fibers in the concrete mixture with long of (3cm) and width of (0.3cm) with and without using of silica fume (SF) with (5 and 10)% of cement weight. Fibers of plastic waste added as a percentage of concrete volume. These percentages were (0.5 and 1)%. Reference concrete mix was also made for comparative purposes. Mechanical properties were tested included compressive and splitting tensile strength. Results showed that, there was an increasing in splitting tensile strength of the mixes containing plastic fibers with (SF) (5)% more mixes included plastic fiber with (SF) equal to 1% of cement weight. At 28 days according to reference concrete , the increasing percentages were (9%, 17.67%) for (0.5%,1%) plastic fibers. (8%, 15%) for plastic fibers with (SF) equal to (5%) and (5%, 3.34%) for plastic fibers with (10%) (SF). There were a decreasing in compressive strength for mixes containing plastic fibers and this decreasing increased with the percentage of plastic fibers. According to the reference concrete the decreasing values of compressive strength at (28 days) were (9.82%, 22.12%) for (0.5%, 1%) plastic fibers, (5.72%, 17.08%) for (0.5%, 1%) plastic fibers with (5%) (SF) and (6.78%, 19.04%) for plastic fibers (0.5%, 1%) with (SF) (10%) respectively.


Article
Modification of Soil Used in Core of Earth Dams
تحسين خواص التربة المستخدمة في لب السد الترابي

Authors: Hassan A. Omran حسن علي عمران --- Noura B. Ibraheem نورة باسم ابراهيم
Journal: Iraqi Journal of Civil Engineering المجلة العراقية للهندسة المدنية ISSN: 19927428 Year: 2018 Volume: 12 Issue: 2 Pages: 40-46
Publisher: University of Anbar جامعة الانبار

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Abstract

The earth-fill dams are simple structures which are able to prevent the sliding and overturning because of their self-weight. Due to lack of suitable clay materials, the dams may be designed as zoned core which is composed of three vertical zones contains central impermeable core and two permeable shells on their two sides of the core. Impervious core is used in zoned earth dam to reduce the quantity of seepage through the body of the dam and to relief part of risk of piping and erosion in the downstream side. This study aims to study the soil properties that is used as a core of earth dam through a series of laboratory experiments that were carried out a several soil samples mixed with both lime and silica fume, in order to stabilize the soil. The process of stabilization aims to increase the soil strength and reducing its permeability and compressibility. Test results show that adding lime and silica fume to the soil decreases the permeability of soil with different cases of study, the percentage of decreases in case of standard compaction about (21%-90%) while in modified compaction test the permeability decreases in range (41.7%-91.3%). Also the unconfined compressive strength of the soil increasing significantly in both cases of compaction which were standard and modified. When add the materials, these values were increased in range (76%-90%) for samples from standard compaction test, while it being (0.21%-42%) in modified compaction test.

تعتبر السدود الترابية من ابسط المنشأت الهيدروليكية التي تعتمد على وزنها لمقاومة الانزلاق والانقلاب.ويمكن اعتماد تصميم السدود الترابية على أساس تقسيمها الى أجزاء محددة عندما تكون التربة الطينية ذات النفاذية القليلة, حيث يمكن ان يقسم جسم الى ثلاثة اجزاء هي الجزء المركزي غير نفاذ الذي يمثل اللب, وجزئين نفاذين على جانبي اللب الطيني.التجارب المختبرية التي تم اجراءها على عدة نماذج للتربة الطينية الممزوجة بمادتي مسحوق السيليكا (silica-fume) والجص (lime) لغرض تحسين خصائص التربة المستخدمة والمتمثلة بزيادة المقاومة وتقليل النفاذية والانضغاطية. بينت نتائج البحث ان خلط التربة الطينية مع مادتي مسحوق السيليكا (silica-fume) والجص (lime) يؤدي الى تقليل نفاذية التربة في مختلف الحالات التي تم دراستها, نسبة التناقص في حالة الرص القياسي تتتراوح بين (21%-90%) بينما نسبة هذا التناقص تتتراوح بين (41,7%-91,3%) في حالة الرص المعدل.كذلك مقاومة الانضغاط الغير محصور ازدادت في حالتي الرص القياسي والرص المعدل عند إضافة المادة هذه القيم ازدات تقريبا بمقدار (76%-90%) بالنسبة للرص القياسي بينما تصبح (0.21%-42%) بالنسية للرص المعدل.

Keywords

Earth dam --- core --- soil modification --- lime --- silica fume


Article
BEHAVIOR OF SELF COMPACTING CONCRETE SUBJECTED TO SULPHURIC ACID
سلوك الخرسانة الذاتية الرص المعرضة الى حامض الكبريتيك

Authors: Mohammed Mosleh Salman --- Luma Abdul Ghani Zghair
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 5 Pages: 1-9
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Self-Compacting Concrete mixes (SCC) is increasingly being used in many application some of which are susceptible to an Aggressive Environment such as sulfuric acid solution. In this study SCC incorporating silica fume, chalk powder and hybrid fibers were used in casting twelve specimens with a dimensions of (1000× 200× 100) mm , in three groups. The specimens in the first group were cured in normal environment for 28 days, while those in the second and third groups were subjected to sulfuric acid solution of 0.5% for six and ten months, respectively. The flexural tests of the specimens were evaluated by testing the specimens under two-concentrated point loading until failure. The experimental results show that after chemical exposure for ten months, using of chalk powder or hybrid fibers enhances the resistance to sulfuric solution


Article
“Effect of Polypropylene Fibers on Producing Sustainable Accelerated Hardened Cementitious Materials”
تأثير ألياف البولي بروبلين في أنتاج مواد أسمنتية مستدامة سريعة التصلب

Authors: Ziyad Majeed Abed --- Maan Salman Hassan --- Rana Hameed Faisal
Journal: journal of kerbala university مجلة جامعة كربلاء ISSN: 18130410 Year: 2018 Volume: 16 Issue: 2 Pages: 150-159
Publisher: Kerbala University جامعة كربلاء

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Abstract

The aim of this research is to produce environmental friendly cementitious materials using polypropylene fibers as recyclable reinforcement materials and silica fume (side-product in manufacturing of ferro-silicon alloys and silicon metal) material. The manufacturing process includes using accelerating curing with carbon dioxide for the fresh cementitious mixtures to decrease setting time and improve hardening, particularly in precast concrete plants.Mix proportions used in this research were cement: silica fume: Sand (1: 0.75: 1.3) and 0.5 w/c ratio. Also, four percentages of polypropylene fibers are used (0, 0.3, 0.9, and 1.5%) by weight of cement. All specimens are exposed to 100% of carbon dioxide gas concentration for 2 hours. Compressive, flexural, and direct tensile strengths have been tested at 7 and 28 days. The results show a significant improvement of flexural strength and direct tension for specimens. The increasing percentages of flexural strength and direct tension with (1.5% polypropylene) compared with control mixture at age 28 days were about (+ 28%) and (+ 117%) respectively.

ان الهدف الرئيسي في هذا البحث هو انتاج مواد سمنتية صديقة للبيئة باستعمال الياف البولي بروبلين كمواد تسليح قابلة لاعادة الاستعمال وكذلك مادة غبار السيليكا (منتج ثانوي في صناعة سبائك الحديد والسيليكون ومعدن السليكون). ان عملية التصنيع تتضمن الانضاج المعجل باستعمال ثنائي اوكسيد الكربون للخلطات السمنتية الطازجة من اجل تقليل زمن التجمد وتحسين التصلب وخصوصا في معامل الخرسانة مسبقة الصب .نسب الخلط المستعملة في هذا البحث هي سمنت: سيليكا فيوم :رمل ( 1.3 : 0.75 : 1) ونسبة الماء الى السمنت هي 0.5 .اضافة الى ذلك، تم استعمال اربع نسب من الياف البولي بروبلين هي (0,0.3,0.9,1.5 )% من وزن السمنت. تم تعريض كل النماذج الى غاز ثنائي اوكسيد الكربون وبتركيز 100% ولمدة ساعتين . تم فحص مقاومة الانضغاط , الانثناء, والشد المباشر بعمر 7 و 28 يوم . بينت النتائج تحسن ملحوظ في مقاومة الانثناء والشد المباشر للنماذج .نسب الزيادة في مقاومة الانثناء والشد المباشر باستخدام نسبة (1.5% بولي بروبلين) مقارنة مع الخلطة المرجعية وبعمر 28 يوم كانت حوالي (+28%)و(+117%) على التوالي .

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