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Article
Pullout strength behaviour of self-compacted concrete in aggressive solutions

Authors: Maha Sabhan --- Adnan Al-Sibahy
Journal: Al-Qadisiyah Journal for Engineering Sciences مجلة القادسية للعلوم الهندسية ISSN: 19984456 Year: 2019 Volume: 12 Issue: 4 Pages: 260-266
Publisher: Al-Qadisiyah University جامعة القادسية

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Abstract

The aim of this study was to investigate the pullout strength behaviour of self-compacted concrete under corrosion conditions. Block samples with two configurations were formulated. A total number of twelve block samples in addition to 24 cubes were tested. The hardened concrete samples were either cured in tap water or exposed to salt solution. A suitable epoxy was used for coating part of the formulated samples. The preliminary mechanical properties and the rate of corrosion were firstly measured, the pullout was then carried out. A comparison was also made with the relevant code of practice. The results obtained showed that both compressive strength and density features exhibited a notable increase at an early age when the samples are exposed to salt solution. The adverse effect of such curing condition appeared at the later ages when the corrosion rate became more intensive. The highest decrease in the value of pullout strength was observed for the reinforced concrete block samples containing epoxy coating reaching to 44.5% less than those cured in tap water.


Article
A REVIEW OF BOND BEHAVIOR OF GLASS FIBER REINFORCED POLYMER BARS WITH CONCRETE

Author: Mohammed Hashim Mohammed
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 3 Pages: 142-157
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

One of the most serious problems of reinforced concrete structures is corrosion of embedded reinforcing steel bars especially in aggressive environments. To control steel corrosion, several approaches have been followed but do not introduce 100% corrosion resistance and guaranteed long-term performance. Glass Fiber Reinforced Polymer (GFRP) bars are considered to be an ideal alternative to overcome corrosion problem in steel bars because of their high corrosion resistance. This paper discusses the main topics related to the use of GFRP bars as reinforcement in structural reinforced concrete applications and presents an overview to the available literature especially in GFRP bond behavior. The main conclusions are: standardizing the manufacturing process of GFRP bars are needed in order to limit the contradictory results of their performances due to the high differences in the products characteristics, and that the available design guidelines have much conservative equations, so they are recommended to be revised to be more practical.


Article
Assessment of Dowel Bars Performance in Concrete Pavement Containing Crumb Rubber of Tires

Authors: Muhaned G. Al-Khuzaie --- Basim H. Al-Humeidawi --- Ra'id F. Al-Sa'idi
Journal: Al-Qadisiyah Journal for Engineering Sciences مجلة القادسية للعلوم الهندسية ISSN: 19984456 Year: 2019 Volume: 12 Issue: 4 Pages: 214-219
Publisher: Al-Qadisiyah University جامعة القادسية

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Abstract

Solid waste management is one of the big challenges facing most countries around the world. Reusing these wastes in construction project represent one of the most efficient ways to consume these wastes and reduces the demand on natural sources. The Crumb Rubber (CR) of tires is a source of a huge amount of solid waste that can be reused in construction projects such as paving of roads. The current research presents an experimental investigation for the dowel bars performance in rubberized concrete pavement. The research involves conducted pullout tests for dowel bars cast in concrete pavement contains a different percentage of CR particle (2%, 4%, and 6% of total aggregate) as partial or total replacement to aggregate on sieves No. 16 and No. 50. Four cases of dowel bars surface were investigated. The results of the study showed that adding CR particles to concrete can significantly reduce the bond between the dowel bars and surrounding concrete pavement which allows for more free movement of dowel bars and reduce joint lockup. The use of treated CR by NaOH solution with standard dowel bars (epoxy coated lubricant steel dowels) can give a superior reduction in pullout load. The reductions were 45%, 66%, and 83% in pullout load for the percentages of 2%, 4%, and 6% crumb rubber respectively compared with the reference mix.


Article
Tensile Strength of Short Headed Anchors Embedded in Steel Fibrous Concrete
مقاومة الشد للمثبتات القصيرة ذات الرؤؤس المطمورة في خرسانة ليفية فولاذية

Authors: S. A. Al- Ta'an سعد علي الطعان --- A. A. Mohammed عبد القادرعلي محمد
Journal: AL-Rafdain Engineering Journal (AREJ) مجلة هندسة الرافدين ISSN: 18130526 Year: 2010 Volume: 18 Issue: 5 Pages: 35-49
Publisher: Mosul University جامعة الموصل

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Abstract

ABSTRACT This paper deals with the tensile behaviour and strength of cast-in-place short headed anchor bolts embedded in both normal concrete (NC) and steel fibre reinforced concrete (SFRC). Four volume fractions (vf =0.4%, 0.8%, 1.2%, and 1.6%), two aspect ratios (lf / df =19.63, 36.33), three bolt diameters (db =8, 10, 12mm), and four embedment depths (hef =25, 37.5, 50, 62.5mm) were used. More than (108) specimens were tested under monotonic tensile loading. Only (90) specimens were failed by large concrete failure cone exceeding the dimensions of the specimen and the cone breaks into pieces in most cases (concrete failure), while the other specimens were failed by yielding or fracture of the bolts (steel failure). Tests results showed that breakout capacity ( ) of the anchors were significantly enhanced by the addition of steel fibers to concrete and the size of the failure cone in (SFRC) specimens were smaller than the size of failure cones in (NC). Key word: Breakout capacity, cast-in-place, failure cone, headed anchor bolt, pullout test, steel fibers.

الخلاصةيتضمن هذا البحث دراسة مقاومة وسلوك الشد للبراغي القصيرة ذات الرؤؤس المطمورة في خرسانة عادية وخرسانة مسلحة بالالياف الفولاذية. استعملت اربع نسب للالياف الفولاذية (0.4%، 0.8%، 1.2%، و%1.6)، نسبتين باعيتين للالياف (19.63 و 36.33)، ثلاثة اقطار للبراغي (8، 10، و mm 12)، واربعة اعماق دفن (25، 37.5، 50، و62.5mm ). تم تحضير أكثرمن 108 نموذج وفحصت تحت تأثير حمل شد متزايد. فشلت 90 من النماذج فقط على شكل مخروط خرساني زادت ابعاده عن ابعاد النماذج وانقسم المخروط الى عدة أجزاء في معظم الحالات، بينما فشلت النماذج الاخرى بانقطاع البرغي (فشل الحديد). أظهرت النتائج أن مقاومة الشد للبراغي تتحسن بشكل ملحوظ باضافة الالياف الفولاذية وان حجم المخروط الخرساني أقل في الخرسانة الليفية عما هوعليه في الخرسانة الاعتيادية.

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