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Article
Improving the Compatibility between Polymer-, Pozzolanic Cement-Based Repairing Materials and Concrete Substrate
تحسين التوافق بين مواد الإصلاح البوليمرية- البوزولانية السمنتية والجسم الخرساني

Authors: Qais J. Frayyeh --- Maan S. Hassan --- Tahseen D. Saadoon
Journal: Engineering and Technology Journal مجلة الهندسة والتكنولوجيا ISSN: 16816900 24120758 Year: 2013 Volume: 31 Issue: 4 Part (A) Engineering Pages: 661-676
Publisher: University of Technology الجامعة التكنولوجية

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Abstract

In this study, the compatibility of five different cement based repair materials and substrate concrete was investigated in three stages. First stage includes studying the individual properties of repair materials, and also two types of concrete, such as compressive strength, flexural strength, and dry shrinkage using BS 1881: part 116, ASTM C78-06, ASTM C157 -06 test procedure respectively. Second stage includes evaluating the bond strength of composite cylinder for different combinations of repair materials and substrate concrete. Third stage includes investigating the compatibility using a composite beam of repair material and substrate concrete under third point loading. The experimental results show that one individual property has no crucial effect on the success of concrete repair system. Bond strength and dry shrinkage however has a strong indication about the compatibility.

في هذه الدراسة تم التحري عن التوافق بين مواد الإصلاح البوليمرية- البوزولانية السمنتية والجسم الخرساني وعلى ثلاث مراحل. الأولى: التحري عن الصفات الذاتية لكل من مواد الإصلاح البوليمرية- البوزولانية السمنتية وكذلك لنوعين مختلفين من الجسم الخرساني, مثل مقاومة الانضغاط, مقاومة الانثناء, وانكماش الجفاف وباستعمال المواصفة 116 part ,BS1881:11ASTM C157-06 ,ASTM C78-06 بشكل متتالي. الثانية: تقييم مقاومة الربط للاسطوانة ألمركبه والمصنوعة من أنواع مختلفة من مواد الإصلاح والخرسانة. ثالثا: التحري عن التوافق باستخدام عتبه مركبه مصنوعة من الخرسانة ومواد الإصلاح وفحصها بطريقة التحميل بنقطتين. تبين نتائج الجزء العملي بانة لاتوجد خاصية منفردة لمواد الاصلاح ذات تاثيرحاسم لنجاح نظام الإصلاح الخرساني. بينما توفر مقاومة الربط و وانكماش الجفاف مؤشرا قويا عن مدى التوافق.


Article
EXPERIMENTAL BEHAVIOR OF R.C. BEAMS PARTIALLY MAGED IN FLEXURE AND STRENGTHENED WITH CFRP LAMINATES

Author: Qais F. Hasan
Journal: AL-TAQANI مجلة التقني ISSN: 1818653X Year: 2010 Volume: 23 Issue: 1 Pages: 128-141
Publisher: Foundation of technical education هيئة التعليم التقني

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Abstract

This study presents an experimental investigation on the monotonic flexural behavior and ultimate capacity of reinforced concrete beams partially damaged and cracked in flexure due to applying a 58% of the predicted ultimate flexural load capacity, and then repaired by external strengthening with high strength CFRP (Carbon Fiber Reinforced Polymer) laminates bonded with epoxy resin to the tension face of concrete after doing all the appropriate preparations for the concrete adhesion substrate. Five rectangular reinforced concrete beams were tested to obtain the effect of amount of CFRP laminate on beams cracking behavior, concrete strains, ductility ratios, ultimate loads and failure modes. The results obtained from the adopted repairing and strengthening technique showed a significant effect of external high strength CFRP laminates on improving behavior and capacity of reinforced concrete beams. An increase by 15%- 33% in ultimate load capacities, for the CFRP strengthened beams, was observed over the control beam with conventional reinforcement. This gain in strength was accompanied by a reduction in ductility ratio by 18%- 28% for the CFRP strengthened beams compared with the control R.C. beam. Also, the crack patterns show enhanced performance in crack distribution and propagation for the strengthened beams over the control beam

تشتمل هذه الدراسة على فحوصات مختبرية لتصرف الإنحناء الساكن والحمل الأقصى لعتبات خرسانية مسلحة متضررة جزئياً ومتشققة نتيجة لتسليط 58% من حمل الإنحناء الأقصى المتوقع، ومن ثم تم معالجتها وتقويتها خارجياً بشرائح من ألياف الكربون والتي ألصقت بإستخدام مادة الإيبوكسي على جهة الشد للخرسانة بعد عمل كافة التحضيرات على سطح الخرسانة اللاصق. تم فحص خمسة عتبات خرسانية مسلحة مستطيلة المقطع لمعرفة تأثير كمية شرائح ألياف الكربون على التشقق، الإنفعالات في الخرسانة، نسبة المطيلية،الأحمال القصوى ونوع الفشل. إن النتائج المستحصلة من هذه الطريقة المستخدمة للتقوية أثبتت التأثير الفعال لإستخدام شرائح ألياف الكربون في تحسين التصرف والأحمال للعتبات الخرسانية المسلحة. كانت الزيادة بمقدار 15%- 33% في سعة الحمل الأقصى للعتبات المقواة مقارنة بالعتبات غير المقواة. كما كان هنالك نقصان بنسبة 18%- 28% في مقدار المطيلية للعتبات المقواة مقارنة بالعتبات غير المقواة. وقد أظهرت العتبات المقواة تحسناً في أداء نمط التشقق مقارنة بالعتبات غير المقواة


Article
Evaluation of Fatigue and Impacted bond Strengths of Denture Base Repaired by Using Different Type of Surface Treatment

Author: Ibrahim Hamad Al-Fahdawi ابراهيم حميد الفهداوي
Journal: Tikrit Journal for Dental Sciences مجلة تكريت لعلوم طب الاسنان ISSN: 20731213 Year: 2015 Volume: 3 Issue: 1 Pages: 16-21
Publisher: Tikrit University جامعة تكريت

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Abstract

Objective: Since the 1930s, a variety of resins have been introduced into dental treatments for the construction of dental prostheses and their efficacy has been based on physical, chemical and biological properties. Denture breakage is usually related to faulty design, faulty fabrication, and/or poor materials choice. Purpose: of this study is to investigate (in vitro) the fatigue bond strength and impact bond strength of the denture repaired by light-cured acrylic resins by using different chemical solvents such as acetone, monomer and thiner. Materials and methods: The acrylic resin used are heat-cure, specially designed molds are use to prepare 6 groups of specimens following the manufacturer's instruction (5 specimens for each cured polymerization). Specimens were cut in guiding by standardized positional jig. The ends of specimen saturated by different solvents acetone, thiner and monomer before repairing. To evaluate the impact strength, plastic strips were fabricated as per the dimensions (50×5×4) mm. Alternating bending fatigue machine was used to test the ten samples with the dimension of (70102.5) mm. Result: impact bond strength with monomer solvent higher than thiner solvent and acetone solvent. Fatigue bond strength with acetone solvent higher than thiner solvent and monomer solvent. Acetone, thiner and monomer were applied as solvents, the results of all surface treatments revealed significant difference at (P- value <0.05) in mean value (no significant for fatigue bonde strength but significant with impact bond strength.


Article
STRENGTHENING AND REHABILITATION OF REINFORCEMENT CONCRETE SQUARE COLUMNS CONFINED WITH EXTERNAL STEEL COLLARS
تقوية وترميم الاعمدة الخرسانية المسلحة المربعة بأستخدام الاطواق الحديدية الخارجية

Author: Khamail Abdul-Mahdi Mosheer خمائل عبد المهدي مشير
Journal: KUFA JOURNAL OF ENGINEERING مجلة الكوفة الهندسية ISSN: 25230018 Year: 2016 Volume: 7 Issue: 1 Pages: 129-142
Publisher: University of Kufa جامعة الكوفة

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Abstract

Strengthening and rehabilitation by confinement technique of reinforced concrete columns was investigated. The columns were confined by external steel collars. Behavior and failure load of columns were experimentally investigated. Results show that Confinement in concrete column has improved its strength and ductility. Effect of confined area, size of collar and compressive strength of concrete on strengthening was investigated .Confined area had significant effect on the failure load for strengthened specimens and had more effective on the failure load for repaired specimens. The confinment had clearer effect with low compressive strength of concrete. The result show an increase in ultimate axial load reach to (12.36 – 56.04%) for strengthening columns and (47.5 –96.7%) for reaparing columns.

في البحث الحالي تم دراسة تقوية وترميم الاعمدة الخرسانية المسلحة مربعة المقطع بأستخدام تقنية الحصر( التطويق)حيث تم حصر الاعمدة خارجيا بأستخدام الاطواق الحديدية. تم دراسة سلوك وحمل الفشل للاعمدة عمليا. الدراسة تناولت تاثير مساحة التطويق , حجم الاطواق , و مقاومة انظغاط خرسانة العمود . بينت النتائج ان تقنية الحصر ادت الى تحسين مقاومة ومطيلية الاعمدة. مساحة التطويق ادت الى تطور في حمل الفشل في حالة تقوية او ترميم الاعمدة. كما بينت النتائج ان تأثير التطويق على تقوية العمود يكون اكثر وضوحا عندما تكون مقاومة انضغاط العمود قليلة. بينت النتائج حدوث زيادة بالتحمل يصل الى (12.36 – 56.04 %) في حالة تقوية الاعمدة و (47.5 –96.7%) عند ترميم الاعمدة.


Article
BEHAVIOR OF REPAIRED COMPOSITE MODIFIED REACTIVE POWDER CONCRETE I-SECTION BEAMS WITH OPENING UNDER PURE TORQUE
سلوك العتبات المركبة بعد التاهيل ذات المقطع (I) والمحتوية على خرسانة المساحيق الفعالة المطورة مع فتحات تحت عزم اللي الصافي

Author: Ali Sabah Ahmed
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2017 Volume: 21 Issue: 1 Pages: 39-50
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

In this paper, an experimental study has been conducted to investigate the behavior of composite concrete beams damaged and cracked under pure torsion , and then repaired by external strengthening with high strength CFRP(Carbon Fiber Reinforced Polymer) laminates bonded with epoxy after doing all the appropriate preparations for the concrete adhesion substrate. Four composite modify reactive powder concrete (MRPC) I- beams,1300mm length,100mm web width and 320mm height, with different type of section (Solid & with opening) were tested to obtain the effect of amount of CFRP laminate on beams cracking torque behavior, angle of twist and failure modes. The results obtained from the adopted repairing technique showed a significant effect of external high strength CFRP laminates on effectively restore of section solid the range of 84% to 85.33% of crack torsional strength effectively restore. As well as the results show that effectively restore of section opening by 80%- 82.22% of crack torsional strength.

هذا البحث هو دراسه عمليه للتحري عن سلوك العتبات الخرسانيه المركبه المتضرره والمتشققه تحت تاثير احمال اللي الصافيه ,ومن ثم تم معالجتها خارجيًا بشرائح من ألياف الكربون والتي ألصقت بإستخدام مادة الإيبوكسي بعد عمل كافة التحضيرات على سطح الخرسانة اللاصق.تم فحص اربعه عتبات خرسانيه مركبه من خرسانه المساحيق الفعاله المطوره ذات مقطع (I) بطول 1300mm وعرض الويب 100mm وارتفاع 320mmلمقاطع مختلفه (صلده& مع فتحات) لمعرفه تاثير كميه شرائح الياف الكربون على مقاومه عزم التشقق ,وزاويه الدوران ونوع الفشل .ان النتائج المسنحصله من هذه الطريقه المستخدمه للمعالجه اثبتت التاثير الفعال لاستخدام شرائح الياف الكاربون في استرجاع المقاومه للمقاطع الصلده بحدود 84% الى 85.33% من مقاومه عزم التشقق لهذه العتبات. وكذلك اظهرت النتائج استرجاع المقاومه للمقاطع ذات الفتحات بحدود 80% الى82.22% من مقاومه عزم التشقق لهذه العتبات.


Article
Repairing of Reactive Powder Concrete T-Beams Containing Web Opening by CFRP Strips
اصلاح عتبات خرسانة المساحيق الفعالة ذات المقطع T الحاوية على فتحات في منطقة الجذع بشرائخ االلياف

Authors: Mazin B. Abdulrahman --- Husham Mohammed Rashid
Journal: Tikrit Journal of Engineering Sciences مجلة تكريت للعلوم الهندسية ISSN: 1813162X 23127589 Year: 2019 Volume: 26 Issue: 1 Pages: 9-19
Publisher: Tikrit University جامعة تكريت

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Abstract

In modern buildings, transverse openings are often used beams for the purpose of supplying and service pipes. Due to the presence of the openings in the concrete beams lead to the formation of cracks around the openings due to the stresses concentration in a small area above and below of the opening. The repairing, maintenance, and upgrading of structural members, are maybe one of the most pivotal problems in civil engineering applications. In this research, an experimental work is conducted to study the behavior of the reinforced RPC T-beams that containing openings and repair this beams using CFRP strips. The Experimental program of the present study includes two parts, the first part includes testing of seven reinforced reactive powder concrete RPC T-beams, which casted and tested, one beam is without opening as a reference beam and the rest, were provided with an opening. and these beams are divided into two groups. The first group was used to study the effect of the openings shape (circular and square) and the second group was used to study the effect of the openings locations, which consists three locations (Lc/2, Lc/3 and Lc/4). These are measured from the support center to the openings center. While the second part including a repaired all beams in the first part the using carbon fiber polymer. The test results indicated that the presence of openings in the beams web caused a reduction in the reinforced RPC T-beams ultimate load carrying capacity with about (10-55)%, Also lead to increasing in deflection compared to control beam before repairing at same loading. Studying the shape effect showed that the beams with square openings have average ultimate load carrying capacity lower by 36% compared with the control beams. While beams with containing circular openings have average ultimate load carrying capacity lower 29%. From the test results, it could be concluded that the presence of the openings in the shear region led to a decrease in ultimate load carrying capacity a about 38% to 49% for opening of opening at (Lc/3 and Lc/4) respectively. While the presence of openings in the flexural region led to a decrease in the ultimate load carrying capacity rate of 11%. Related to the repairing study part it was found that the average ultimate load carrying capacity for repairing beams was 103% compared with the not repairedbeams.


Article
Experimental Investigation of Reinforced Concrete Flexural Beams Strengthened or Repaired with CFRP
التحري العملي لعتبات الانثناء الخرسانية المسلحة المقواة أو المعاد تصليحها بال CFRP

Authors: DAWLAT D. ALI --- Nazar K. Al-Oukaili --- Husain M. Husain
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2009 Volume: 15 Issue: 3 Pages: 3891 -3906
Publisher: Baghdad University جامعة بغداد

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Abstract

Fiber reinforced polymers are typically comprised of high strength fibers (e.g. carbon and glass) impregnated with an epoxy (often termed the matrix). Experimental investigations of the behavior of reinforced concrete beams, strengthened or repaired by CFRP for flexural case have been presented in this paper. The experimental program consisted of 14 test beams. The study took into account strengthened and repaired cases in using CFRP; therefore, similar beams were used once for strengthening and once for repairing to make a comparison between them. All beams had been tested in a simply supported span and subjected to two-point loading while the main variable is the quantity, distribution and location of CFRP. The beams included additional anchorage at the ends of the main CFRP sheet reinforcement to prevent end separation of CFRP sheet. The results of experiments show that the use of CFRP as external strengthening has significant enhancement on ultimate load, crack pattern and deflection. It is observed that the use of external CFRP in strengthening or repairing beams could enhance the ultimate load capacity up to 160% over the capacity of the identical reference (untreated) beam.

الياف التقوية بالبوليمر تتالف بصورة مثالية من الياف عالية المقاومة (على سبيل المثال الكاربون او الزجاج) منغمسة بالايبوكسي. التحريات العملية لسلوك العتبة الخرسانية المسلحة المقواة او المعاد تصليحها بهذه الالياف لحالة انثناء العتبة تم تقديمها في هذا البحث. البرنامج العملي تالف من 14 عتبة فحص (عتبات انثناء) لدراسة اخذت بنظر الاعتبار حالتي التقوية واعادة التصليح لذلك صنعت عتبات متشابهه ستستعمل واحدة منها للتقوية واخرى لاعادة التصليح لعمل مقارنة بينهما. كل العتبات تم فحصها بفضاء بسيط الاسناد ومتعرضة الى نقطتي تحميل بينما المتغيرات الرئيسية كانت كمية توزيع وموقع شرائح الالياف. مجموعة عتبات الانثناء تضمنت تثبيت اضافي في نهايات صفيحة تقوية الCFRP الرئيسي لمنع اانفصال صفيحة CFRP . نتائج الفحوصات العملية بينت أن استعمال CFRP كتقوية خارجية له تاثير كبير على الحمل الاقصى، شكل التشقق والهطول. تم الاستنتاج بان استعمال الCFRP الخارجي في التقوية او اعادة تصليح عتبات الانثناء يمكن ان تعزز سعة الحمل الاقصى الى 160% من سعة العتبة المصدرية المثالية.


Article
STUDY THE EFFECT OF MICROWAVE HEATING ON PHYSICAL PROPERTIES OF ASPHALT

Authors: Raad Yahya Faleh --- Wathiq Kareem Saleh --- Haider Salman Mohammed
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2018 Volume: 22 Issue: 2 (Part-5) Pages: 127-135
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

In this work, the effect of microwave on asphalt (heating rat, resistance to deformation and retain stability) was examined. Two different asphalt samples were used. The first, standard asphalt (A) and the second one with %2 of sulfur in bitumen (B) have been exposed to microwave. The measured temperature on the surface showed an increase up to 120 ºC in 5 minutes for sample A, while it reached to 145 ºC for sample in the second cycle of exposure to microwave in the same time. The increase rate in temperature for B samples was slightly lower. The presence of sulfur in asphalt reinforced the physical properties and the asphalt became more resistant to water and rutting for sample B after exposure to microwave radiation. Theoretically, the rise of temperature was found to be (0.64 ºC/minute) for one ton of asphalt needing microwave power energy of 1000 watt, but practically, some of this energy loss can be attributed to the conductivity and the penetration of the wave out of asphalt region. This study proved that the better incident angle reducing this loss by using the equation ɵ=sin-1(x/(1/ α)), and was found to be 28ºC and 37ºC for sample A and B respectively. The results showed the possibility of using microwave radiation in repairing the damaged roads asphalt with economic effective and green method.

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