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Article
Using Ultrasonic Pulse Velocity Test to Assess the Effect of Water-Cement Ratio on the Compressive Strength of Concrete

Author: Ziwar Zebari
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2019 Volume: 25 Issue: 5 Pages: 79-86
Publisher: Baghdad University جامعة بغداد

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Abstract

This study aims to find the effect of water-cement ratio on the compressive strength of concrete by using ultrasonic pulse velocity test (UPVT). Over 230 standard cube specimens were used in this study, with dimensions of 150mm, and concrete cubes were cured in water at 20 °C. Also, the specimens used in the study were made of concrete with varied water-cement ratio contents from 0.48 to 0.59. The specimens were taken from Diyarbakir-Turkey concrete centers and tested at the structure and material science lab, civil engineering, faculty of engineering from Dicle University. The UPV measurement and compressive strength tests were carried out at the concrete age of 28 days. Their UPV and compressive strength ranged between (3.89-4.66km/s) and (17.74-40.56MPa) respectively. The experimental results showed that although the UPV and the compressive strength of concrete are related, also, the UPV and compressive strength have a relation with the rate of the water-cement ratio of concrete.


Article
EFFECT OF CEMENT, LIMESTONE AND HYDRATED LIME ON SETTING TIME AND COMPRESSIVE STRENGTH OF LOCAL GYPSUM

Author: Sana Taha Abdul-Hussain
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 2 Pages: 120-132
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

This paper consists of studying the effect of adding different ratios of cement, limestone powder and hydrated lime on setting time and compressive strength of gypsum which available in local market which does not conform to Iraqi Standard Specification (I.Q.S) No.28/1988. The adding materials are low-cost and available in local market and can be used to improve setting time and compressive strength for gypsum which are considered as the most important properties if it used as mortar or in finishing. The adding ratios of cement were (10, 20, 30, 40 and 50) % from gypsum weight, the ratio of (50%) was the best ratio as regarded to setting time and compressive strength. They are (10.33 minutes), (8.04 N/mm2) respectively. For the limestone powder addition, the ratios were (10, 20, 30, 40, 50 and 60) % from gypsum weight. The results showed that, the ratio of (10%) was the best in compressive strength (6.2 N/mm2) and ratio of (60%) was the best in setting time. At adding hydrated lime, the ratio of addition (2.5%) gave compressive strength (7.51 N/mm2) and the ratio of (12.5%) gave setting time (14.15 min.).


Article
MECHANICAL PROPERTIES OF MRP LIGHTWEIGHT CONCRETE AND EFFECT OF COMPRESSIVE STRENGTH ON SHEAR CAPACITY OF BEAMS

Authors: Wissam Kadhim AlsaraJ --- Layth Abedalbari Aljaberi --- Hayam Yousuf Alhamdani
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 4 Pages: 145-154
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The objective of this study is to investigate the effect of compressive strength on the shear capacity of Modified Reactive Powder Lightweight Concrete (MRPLWC) Beams. The structural behavior of (3) MRPLWC beams without web reinforcement under two point loading system , are studied. Three percentage of Silica Fume (SF) were used to improve the compressive strength of MRPLWC. The experimental results pointed that a positive correlation between the compressive strength and diagonal cracking load and ultimate shear load. Increasing the compressive strength from (89.53 MPa) to (90.3) MPa lead to increase the diagonal cracking load Vcr and increasing ultimate shear load Vu .


Article
A Comparative Investigation on Mechanical Properties of Various Fibers Reinforced Concrete

Authors: Hussein A. Jaber Aya A. Shaher --- Ahmed M. Al-Ghaban
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2019 Volume: 37 Issue: 1 Part (A) Engineering Pages: 28-36
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

The present work presents an investigation the effect of addingvarious fiber materials such as (glass, nylon, and carbon) into the concrete mix for inspectingand compare the mechanical properties of different fibers reinforced concrete. Two different fiber length states of (short=3cm and long=10cm) are used in this work. The concrete of ordinary Portland cement of (1:1.5:3), (cement: sand: gravel), were mixed with each of the fiber materials at four different weight percentages (0, 0.4, 0.8, and 1.2) wt% per cement content. Compressive strength and flexural strength were experimentally investigated of different fibers reinforced concrete specimens after curing for 28 days. The results showed that the incorporation of various fibers with the concrete mix generally improved the strength of concrete by improvingthe toughness. The flexural strength of concrete with addition of various fibers was strongly enhanced than compression. Addition 0.8% of nylon fiber to concrete resulted in the maximum increase of itscompressive strength, reaching the rate of increasing to 11.08% for short fiber and 20.75% for long fiber. Addition 1.2% of nylon fiber to concrete mix resulted in the maximum increase of the flexural strength, reaching rate of increasing to 120.02% for short fiber and 211.49% for long fiber. Increasing the length of fibers increases the strength of the concrete but a little extent. Among these fibers, nylon containing concrete composite exhibits promising mechanical strength that could be easily used as low-cost partitioning wall, false ceiling,and other household purposes.


Article
DEVELOPING SELF-CURING CEMENT SAND MORTAR USING SODIUM POLYACRYLATE

Authors: Sa'ad Fahad Resan --- Sajid Kamil Zemam --- Musab Sabah Abed
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 5 Pages: 95-107
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

As the sustainable construction intends to optimize the use of natural resources and because of the important of water resources, the self -curing could be assigned as sustainable strategy.This study introduces self-curing cement sand mortar with specific properties concern compressive strength, consistency by using sodium polyacrylate as additive. The sodium polyacrylate has wide ranges of uses for many purpose, for its ability to absorbe water and its good mechanical, physical and chemical properties. This study assesses the possibility of using it with traditional raw materials for developing self-curing high workability cement sand mortar which could be useful in many construction applications such as ferrocement slabs and building partitions. The study assigned the possibility of using sodium polyacrylate in gel fashion within cement sand mix as efficient additives for self-curing, as well as its positive effect upon compressive strength and consistency of cement sand mortar comparing with specimens cured with traditional technique of immersing them within water for week. Specimens of sodium polyacrylate to cement ratio (S/C) between 1 to 5 % as gel (with constant water cement ratio, W/C=50%) developed significant strength improvement in absent of any curing techniques, compressive strength upgrading ratio assigned between 1.12 to 1.25 with respect to specimens cured by water for seven days while excellent ratio (1.37) associated with positive effect of specific W/C ratio beside sodium polycraylate effect.


Article
EFFECT OF DIFFERENT TYPES OF LIGHTWEIGHT AGGREGATE ON STRENGTH AND MODULUS OF ELASTICITY OF CELLULAR CONCRETE

Authors: Suhad Mohammed Abd --- Dunay Khalil Ismail
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 5 Pages: 193-206
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

The objective of this study is to improve properties of structural foamed concretes by adding fine and coarse lightweight aggregate. The materials that used in this study were fly ash as fine material and various type of lightweight aggregate (Leca, porcelanite). The mechanical properties included fresh and hardened density, compressive strength and elasticity modulus were tested in this study. The results show increases in compressive strength and modulus of elasticity by increasing the percentage of fine aggregate (fly ash).The optimum percent is 50% for fine aggregate (fly ash).The compressive strength decreases with increasing the percentage of lightweight coarse aggregate .The modules of elasticity increases by increasing the replacement percentage of fly ash . The addition of lightweight coarse and fine aggregate affect on the percentage of foam need be added to the mix for the desired density. Type of aggregate have significant effect on compressive strength and modulus of elasticity for foamed concrete. Flyash increase in compressive strength about (39%). Light weight aggregate decrease in compressive strength about (2-50) %. Flyash increase in modulus of elasticity about (10-56)% and light weight aggregate increase in modulus of elasticity about (1-20)%. Fly ash and lightweight aggregate (Leca and Porcelanite) improved the properties of foamed concrete.


Article
TREATMENT FLY ASH OF AL MUSAYYIB THERMAL POWER PLANT TO BE USED AS A POZZOLANIC MATERIAL

Authors: Rusul H. Al Rammahi --- Fadhil A. Rasin --- Faris H. Al Aani
Journal: KUFA JOURNAL OF ENGINEERING مجلة الكوفة الهندسية ISSN: 25230018 Year: 2019 Volume: 10 Issue: 3 Pages: 90-99
Publisher: University of Kufa جامعة الكوفة

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Abstract

Crude oil ash is the residue that is produced during oil combustion for instance fly ash, bottom ash or boiler slag which was primarily produced from the combustion of coal. With growth in oil burning power station, huge amount of fly ash considered as organic materials which are normally disposed in an on-site disposal system without any commercialization purpose. Previous researchers have studied the extraction of silica from agricultural wastes such as palm ash and rice husk ash (RHA) and FA (fly ash) by using leaching treatment method. In this study, the weaker acid, citric acid solution was used to replace the strong acid in leaching treatment to process. Result showed that the loss on ignition materials can be decrease to 12%. Meanwhile the silica can be extracted up to 54.4% from FA using citric acid leaching treatment under the optimum reaction time of 60 minutes with solution temperature of 60°C and concentration of citric acid 5% receded by gradual combustion at 900°C for 3 hours.


Article
Influence of Mix Water Quality on Compressive Strength of Making Concrete

Authors: Sheelan Mahmoud Hama --- Ibtihal A. Mawlood --- Nahla N. Hilal
Journal: Iraqi Journal of Civil Engineering المجلة العراقية للهندسة المدنية ISSN: 19927428 Year: 2019 Volume: 13 Issue: 1 Pages: 19-22
Publisher: University of Anbar جامعة الانبار

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Abstract

The influence of concrete mixing water quality on the compressive strength of concretes was investigated in this study. During the study, the compressive strength (CS) of the concretes was determined at 7, 14, and 28 days age. This study used 8 types of water of varying qualities as concrete mixing water (water with 71 UTN impurity level, water with 250 UTN impurity level, water with 1000 UTN impurity level, well-sourced water, acidified water, and alkaline water). Potable water was used as reference water. The results indicated that the lowest CS has been obtained by using alkaline water at a concrete age of 7 days while the usage of water with 250 UTN impurity level as a concrete mixing water yielded the highest CS. in addition, the lowest CS has been obtained when using a mixing water of alkaline at a concrete age of 14 days while the highest CS resulted from using water with 71 and 250 UTN impurities levels. Furthermore, the usage of water with 71 UTN impurities level and an acidic water as a concrete water mixing gave the lowest CS at twenty eight days concrete age, while using magnetic water and water with 250 UTN impurities as concrete mixing water resulted in the highest CS. The use of water with 250 UTN impurities as concrete mixing water favored CS development at all concrete ages. These obtained results have shown a various effects of different impurities which significantly indicate that only a few water impurities affect the concrete’s CS seriously..


Article
Use of Alum and Polyelectrolyte Coagulants in Mixing Water in Concrete Bunkers Building or Construction
إستخدام مخثرات الشب والبولي ألكتروليت في ماء الخلط للخلطات الخرسانية المستخدمة في إنشاء السواتر

Author: Ako Rashed Hama آكو رشيد حمه
Journal: Sulaimania Journal for Engineering Sciences مجلة السليمانية للعلوم الهندسية ISSN: 24101699/24156655 Year: 2019 Volume: 6 Issue: 1 Pages: 11-28
Publisher: university of Sulaimania جامعة السليمانية

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Abstract

This paper examines the possibility of using water treatment plant’s sludge [WTP] in mixing water in preparing high strength concrete bunkers. The two main chemical coagulants used in Dokan WTP 70 km southwest of Sulaimani city in Iraq, are alum and polyelectrolyte and they produce a coagulant’s sludge which settled at the end of sedimentation process on the bottom of the clarifier tanks. In this study, the two chemical coagulants alum and polyelectrolyte used as a concrete additives. Samples of the raw water taken from the inlets and have been tested continuously for a time period of 12 months during summer and winter seasons especially at the beginning of the stratification periods of Dokan Lake (source of the treatment plant). The tests included jar tests and turbidity of the samples, then determining the optimum quantity of each of alum and polyelectrolytes. So the maximum amount of the alum was 15mg/L while for polyelectrolyte was 10mg/L. Those two maximum high values of rates of alum and polyelectrolytes and their hybrid mixing rates have been used in preparation 7 concrete prototype bunkers with dimensions of 80cm x 80cm x 15cm with an admixture rates of 15mg/L alum, 15mg/L polyelectrolyte, 10mg/L alum, 10mg/L polyelectrolyte , 10mg/L alum with 5 mg/L polyelectrolyte, 5 mg/L alum with 5 mg/L polyelectrolyte and zero mg/L for both of them (blank). Two different types of tests have been performed for the prepared concrete bunkers; the in-lab compression tests for the cube samples of the prototypes concrete and the outdoor field shouting test for the prepared concrete bunker prototypes using 12.7 mm gun fire bullets and a shooting 100m from the target. Concrete compression laboratory tests have been conducted for 7,21and 28days aged concrete prototype bunkers while the depth, length and the diameter of the cracks and punching of the bullet hitting locations on the targeted prototype concrete bunker were measured. The results of this research reveals that adding alum along either in 15mg/l or 10 mg/ l doses in the three aged concrete 7,21,and 28 days will affect inversly on the concrete compaction strength by a (1 – 8)% while adding the other mensioned doses (polyelectrolyte along with different doses 10mg/l or 15 mg/l and a hybird doses of alum 10mg/l mixed with polyelectrolite 10mg/l ,will help in increasing the concrete compression strength of the concrete by 3.5% to 12%. Through out the tests its clearly appeared that the optimum coagulant in increasing the capacity of the concrete is polyelectrolyte and with a dosage of 15mg/l and it helps to increase the capacity of the concrete to 9% at 7days , 11.5 % at 21days and 13% at 28days from the age of the concrete .The results showed that the penetration depth for all the seven concrete bunker prototypes, evaluates each prototype performance via their penetration depths, because the penetration depth of the bullet is the most important variable in selecting the best performance concrete bunker prototype among all of them. The results also showed that the minimum penetration was 1.7 cm of polyelectrolyte used coagulant prototype of 15mg/L, and the maximum ratio about 2.2cm for the concrete banker prototype containing 15 mg/L of polyelectrolyte coagulant in mixing water of the concrete mixture used in it. Also the smallest diameter as a result of shooting test was 10 cm for this prototype while the largest diameter was 20 cm for the bunker prototype containing 10 mg/L of polyelectrolyte coagulant in mixing water of the mixture used in it.

تم في هذه الدراسة إستخدام المياه الغنية بمادتي الشب والبولي ألكتروليت اللتين هما من اكثر المخثرات شائعة الإستخدام في محطات التصفية كمحطة دوكان لتصفة مياه الإسالة والواقعة جنوب شرق مدينة السليمانية اذ تم إستخدامها كماء خلط في الخلطات الخرسانية عالية المقاومة والمستخدمة في إنشاء السواتر الخرسانية اذ تم إستخدام جرعات مختلفة من الشب والبولي ألكتروليت بالإعتماد على القيم القصوى للإستهلاك في المحطة خلال فترة زمنية مقدارها سنة اذ بلغت 15 ملغ/ لتر من الشب و 10 ملغ/لتر من البولي ألكتروليت. تم إنشاء سبعة نماذج من السواتر الخرسانية بأبعاد 80 سم x80 سم x 15 سم. كانت نسب الاضافة للمواد المخثرة الكيميائية الى ماء الخلط 10 و 15 ملغ/ لتر من شب لوحدهما ، 10 و 15 ملغ/لتر من البولي ألكتروليت لوحدهما ، و 10 ملغ/لتر من شب مع 5 ملغ/لتر من البولي ألكتروليت معا ، 5 ملغ/لتر من الشب مع 5 ملغ/لتر من البولي ألكتروليت معا وكما تم مقارنة الخلطات الحاوية على هذه النماذج من ماء الخلط مع خلطة مرجعية ذات ماء خلط إعتيادي ) غير حاوي على الشب او البولي اليكتوليت( . استخدم نوعان من الفحوصات لغرض معرفة مدى تأثر مقاومة الخرسانة عند إضافة تلك المواد وهما فحص مقاومة الإنضغاط للمكعبات والفحص الموقعي بإستخدام الرمي من رشاش آلي ذو ذخيرة حية بعيار 12.7 ملم من موقع ثابت وعن مسافة ثابتة تبلغ 100 م. بينت النتائج بان إستخدام الشب في ماء الخلط تقلل من مقاومة الخرسانة للانضغاط بنسبة تراوحت من 1 ٪ الى 8 ٪ في المقابل لوحظ ان إستخدام البولي اليكتوليت بشكل منفرد في ماء الخلط او بشكل مركب مع الشب ادى الى زيادة مقاومة الإنضغاظ بنسبة تراوحت من ) 3.5 الى 13 ٪) اذ عند إضافة 15 ملغ/لتر من البولي اليكتروليت الى ماء الخلط , لوحظ بان نسبة الزيادة في مقاومة الإنضغلط بلغت ) 13 ، 11.5 و 9(٪ عند الأعمار ) 7 ، 21 و 28 ( يوما على التوالي كما أن نسب الزيادة هذه تمثل النسب الأعلى مقارنة بالبقية الخلطات.أظهرت نتائج ألرمي الحقلي على نماذج السواتر والتي تعتبر دليل آخر لمعرفة مدى تأثر النماذج بالمواد المخثرة الكيميائية المضافة كانت أقل قيمة مقاسة لعمق إختراق الذخيرة في النماذج الخرسانية بلغت 1.7 سم للنموذج التي يحتوي على 15 ملغ/لتر من البولي اليكترويت أما أعلى قيمة للعمق كانت 2.2 سم. كما ان أكبر قطر متأثر بالذخيرة كان 18 سم للنموذج الذي يحتوي على 15 ملغ/لتر من البولي أليكتروليت أما أضغرها فقد بلغ 10 سم عند النموذج الذي يحتوى على 15 ملغ/لتر من مادة الشب. بذلك يمكن القول بأن المواد المخثرة الكيمياوية تزيد من مقاومة الإنضغاط للخرسانة المستخدمة في السواتر الخرسانية.


Article
Characteristics of Paper-cement Composite
خصائص المركب الاسمنتي-الورقي

Authors: Harith Mohammed Zaki حارث محمد زكي --- Shakir Ahmed Salih شاكر احمد صالح --- Iqbal Naeem Gorgis اقبال نعيم كوركيس
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2019 Volume: 25 Issue: 4 Pages: 122-138
Publisher: Baghdad University جامعة بغداد

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Abstract

This study “discusses the benefit of “addition waste paper as a “new cellulose material “in mortar mixes. A partial addition of waste paper by cement weight was achieved to produce cement composite mortar. Pulp and paper is the third major industrial dumper of air, soil and water. In recent year, paper and paperboard constitute a greater portion of many countries’ urban solid discarded generation. Beside, it increases characteristic “strength due to existence “of hydrogen links “in the microstructure of “paper. Furthermore, it consume “better thermal protection. The addition percentages “of waste paper used “in this work were (5%, 10%, 15% and 20%) by “mass of cement to measure and evaluate some “properties of the mortar produced (compressive“, direct “tensile, and flexural) strength, thermal “properties such as (thermal conductivity), and “microstructure investigation “like (scanning electron microscope “(SEM)). The results indicated that the fresh mortar “properties affected expressively with higher wastepaper percent. The mechanical properties (compression, direct tensile and flexural strength) were “reduced by increasing the content of waste paper, it reduces to (74%, 50%, and 86%) respectively, with (20%) addition of waste paper than the reference mix. Moreover, using waste “paper with different percentages “led to noticeable “decrease in thermal “conductivity, especially with increasing addition percentages.

تناقش هذه الدراسة فائدة إضافة نفايات الورق باعتبارها مادة سيليلوزية جديدة في الخلطات الاسمنتية. ان هذا المركب الاسمنتي تم تصنيعه بإضافة نفايات الورق، كإضافة جزئية من وزن الاسمنت. وهي تعتبر مواد بناء مستدامة بسبب انخفاض كمية النفايات الورقية من مدافن القمامة أو المكاتب. كذلك انه يكتسب، مقاومة اساسها سبب وجود الروابط الهدروجينية في التركيب المجهري للورق. علاوة على ذلك ان الورق يمتلك عزل حراري جيد. ان نسب الاضافة الوزنية من الورق المستخدمة في هذه الدراسة كانت ( 5%، 10%، 15% و 20%) من وزن الاسمنت لاستكشاف الخواص الميكانيكية للخلطات كمقاومة (الانضغاط،، الشد المباشرة، الانثناء)، الخواص الحرارية مثل (معامل التوصيل الحراري)، و التحريات المجهرية مثل (المجهر الإلكتروني الماسح). وبالمقارنة مع الخلطات المرجعية، وجد أن خواص المونة الطرية تتأثر بشكل ملحوظ بزيادة محتوى النفايات الورقية. كذلك هناك انخفاض في مقاومة (الانضغاط ، الشد المباشرة و الانثناء) مع زيادة نسبة الورق لغاية الوصول الى (74%، 50% و 86%) على التوالي و عندما تكون نسبة الاضافة (20%) من مخلفات الورق بالمقارنة مع الخلطة المرجعية. علاوة على ذلك فان استخدام النسب المختلفة من المخلفات الورقية تؤدي الى نقصان ملحوظ في معامل التوصيل الحراري و خصوصا عند زيادة نسب الاضافة.

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