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Combined effect of fineness modulus and grading zones of fine aggregate on fresh properties and compressive strength of self compacted concrete
التاثير المشترك لمعامل النعومة ومناطق تدرج الركام الناعم في الخواص الطرية ومقاومة الانضغاط للخرسانة ذاتية الرص

Authors: Ikram Faroun Ahmed اكرام فرعون احمد --- Abeer Abdulqadir Salih عبير عبد القادر صالح
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2013 Volume: 19 Issue: 6 Pages: 774-785
Publisher: Baghdad University جامعة بغداد

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Abstract

Self-compacted concrete (SCC) considered as a revolution progress in concrete technology due to its ability for flowing through forms, fusion with reinforcement, compact itself by its weight without using vibrators and economic advantages. This research aims to assess the fresh properties of SCC and study their effect on its compressive strength using different grading zones and different fineness modulus (F.M) of fine aggregate. The fineness modulus used in this study was (2.73, 2.82,2.9& 3.12) for different zones of grading (zone I, zone II& marginal zone(between zone I&II)) according to Iraqi standards (I.Q.S No.45/1984).Twelve mixes were prepared, each mix were tested in fresh state with slump, V-Funnel and L-Box tests, then 72 concrete cubes of (100*100*100( mm for different mixes were tested for compressive strength after 7 and 28 days of water curing. Results indicated that the combined effect of fineness modulus and grading zone were clear on the passing ability and little effect of grading zone on flow ability and viscosity of fresh SCC properties. Compressive strength decreases with increasing F.M and no effect of grading zone for F.M higher than 2.90.

تعتبر الخرسانة ذاتية الرص ثورة في مجال تكنولوجيا الخرسانة نتيجة لقابليتها على الانسياب خلال القوالب ، انتشارها خلال حديد التسليح ،رصها لنفسها بتاثير وزنها وفائدتها الاقتصادية . يهدف هدا البحث الى تقييم الخواص الطرية للخرسانة ذاتية الرص ودراسة تاثيرها على مقاومة انضغاط تلك الخرسانة باستخدام مناطق تدرج مختلفة ومعامل نعومة متغير للركام الناعم المستعمل في انتاج هذه الخرسانة . معامل النعومة للركام الناعم المستخدم في هذا البحث كان متغير (2.73،2.82،2.9و3.12) ولمناطق تدرج مختلفة (منطقة تدرج رقم 1ومنطقة تدرج رقم 2ومنطقة تدرج مختلفة تقع بين المنطقتين اعلاه) وفق المواصفة القياسية العراقية رقم 45 لسنة 1984. تم تحضير 12 خلطة من الخرسانة ذاتية الرص ،فحصت بحالتها الطرية بفحوصات الهطول ، V-Funnel و L-Box وبعدها تم صب 72 مكعب خرساني بابعاد (100*100*100) ملم وتم اجراء فحص الانضغاط للخلطات المختلفة باعمار 7 و28 يوم اوضحت النتائج ان التأثيرالمشترك لمعامل النعومة ومنطقة التدرج للخرسانة ذاتية الرص في الحالة الطرية يكون اكثر وضوحا في قابلية الانسياب واقل تأثرا، قابلية الملئ واللزوجة .تقل مقاومة الانضغاط مع زيادة معامل النعومة ويقل تاثير منطقة التدرج مع زيادة معامل النعومة الى اعلى من 2.9 .


Article
Fresh, Mechanical Properties and Impact Resistance Behavior of Eco-Friend Self-Compacted Concrete

Authors: Mohammed T. Nawar --- Alhareth M. Abdulghafor --- Sheelan M. Hama
Journal: AL-NAHRAIN JOURNAL FOR ENGINEERING SCIENCES مجلة النهرين للعلوم الهندسية ISSN: 25219154 / eISSN 25219162 Year: 2019 Volume: 22 Issue: 3 Pages: 208-212
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

In this work, waste glass powder from broken windows and plastic fibers from waste polyethylene terephthalate bottles are utilized to produce an economical self-compact concrete. Fresh properties (slump flow diameter, slump Flow T50, V. Funnel, L–Box), mechanical properties (Compressive strength and Flexural strength) and impact resistance of self-compact concrete are investigated. 15% waste glass powder as a partial replacement of cement with five percentages of polyethylene terephthalate plastic waste were adopted: 0% (reference), 0.5%, 0.75%, 1%, 1.25% and 1.5% by volume. It seems that the flow ability of self-compact concrete decreases with the increasing of the amount of plastic fibers. The compressive strength was increased slightly with plastic fiber content up to (0.75%), about 4.6% For more than (0.75%) plastic fiber. The compressive strength began to decrease about 15.2%. The results showed an improvement in flexural strength and an impact on the resistance in all tested specimens’ content of the plastic fibers, especially at (1.5%) fibers.


Article
EXPERIMENTAL STUDY OF SELF-COMPACTING REINFORCED CONTINUOUS DEEP BEAMS

Authors: Abdul_Qader Nihad Noori --- Adnan Falih Ali
Journal: Journal of Engineering and Sustainable Development مجلة الهندسة والتنمية المستدامة ISSN: 25200917 Year: 2019 Volume: 23 Issue: 1 Pages: 43-65
Publisher: Al-Mustansyriah University الجامعة المستنصرية

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Abstract

Test results of twelve reinforced self-compacted concrete two-span deep beams casted by using self-compacting concrete are reported. The main variables studied were shear span-to-overall depth ratio (a/h), concrete strength (fʹc) and the amount of vertical shear reinforcement ratio (ρv). All specimens had the same dimensions and main flexural reinforcement. Tests pointed out that all beams failed in shear with diagonal splitting mode. It was found that shear span to overall depth ratio (a/h) effects the load carrying capacity of beams such that a decrease of 50 % in that ratio from 1 to 0.5, the cracking load (Pcr) and ultimate load (Pult) increase by average ratios of 29% and 25% respectively. The concrete compressive strength (fʹc) are also had a noticeable influence on the continuous deep beams behavior such that increasing (fʹc) to almost twice from (33.81 to 67.8) MPa led to an increase in the cracking load (Pcr) and ultimate load (Pult) by average ratios of 12.75% and 16.5% respectively. When (ρv) is increased by 80% from (0.25% to 0.45%) a better increase shear capacity of both NSCC & HSCC deep beam having (a/h) ratio of 1.0 (enhancement reached to18.56% and 23.1% respectively) as compared to the reference beams without shear reinforcement (ρv=0).S

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