مطالعه آزمایشگاهی مقاومت ضربه ای بتن معمولی تحت حرارت بالا، با صحت سنجی توسط آزمون‌های SEM و XRD

منصورقناعی, محمدحسین

مطالعه آزمایشگاهی مقاومت ضربه ای بتن معمولی تحت حرارت بالا، با صحت سنجی توسط آزمون‌های SEM و XRD

نوع مقاله : مقاله پژوهشی

نویسنده

محمدحسین منصورقناعی

دکتری تخصصی عمران - سازه، گروه مهندسی عمران، واحد چالوس، دانشگاه آزاد اسلامی، چالوس، ایران

چکیده

افزایش مقاومت و مقابله سازهها در برابر نیروهای وارده ناشی از حوادث گوناگون، همواره مورد توجه مهندسین طراح بوده است. در دهه های اخیر، ایجاد شرایط پدافندی در سازههای با اهمیت زیاد و خیلی زیاد در برابر بارهای ضربهای جزء لاینفک در طراحیهای سازهای است. در این پژوهش آزمایشگاهی یک طرح اختلاط از بتن معمولی حاوی سیمان پرتلند نوع 2 با عیار500 کیلوگرم بر مترمکعب ساخته شد. آزمون مقاومت ضربهای از نوع وزنه افتان در بتن در سن عملآوری90 روزه تحت دمای 21، 300 و 600 درجه سلسیوس بر روی نمونههای بتنی انجام گرفت. در ادامه بهمنظور بررسی بیشتر و صحتسنجی نتایج حاصله، آنالیز میکروسکوپالکترونیروبشی (SEM) و طیفسنجی پراش اشعه ایکس (XRD) در سن عملآوری 90 روزه، بر روی نمونههای بتنی انجام گرفت. نتایج حاصل از آزمونهای این تحقیق ضمن ارزیابی با یکدیگر، با نتایج حاصل از تحقیقات سایرین، مورد مقایسه قرار گرفت. اعمال حرارت در نمونههای بتنی تاثیر قابل توجهی بر روی نتایج حاصله داشت، در این راستا در آزمون وزنه افتان، انرژی جذب شده از 7214/269 (در دمای21 درجه سلسیوس) به 4956/41 (در دمای600 درجه سلسیوس) ژول رسید و افت 92/76 درصدی را دارا شد و شاخص انعطافپذیری از 3/2 (در دمای21 درجه سلسیوس) به 5/2 (در دمای600 درجه سلسیوس) ژول رسید و بهبود 69/8 درصدی را به خود اختصاص داد. در پایان این تحقیق، نتایج حاصل از آزمونهای SEM و XRD در دمای 21 درجه سلسیوس و تحت حرارت بالا، ضمن هماهنگی با یکدیگر، در همپوشانی با نتایج حاصل از سایر آزمونهای این مقاله قرار گرفتند.

کلیدواژه‌ها

20.1001.1.20086849.1402.14.1.1.1

عنوان مقاله [English]

Experimental Study of Impact Strength in Ordinary Concrete under High Temperature, Along with Validation by SEM and XRD

نویسنده [English]

Mohammadhossein Mansourghanaei

Department of Civil Engineering, Chalous Branch, Islamic Azad University, Chalous, Iran

چکیده [English]

Increasing the resistance and resistance of structures against the forces caused by various accidents, has always been considered by design engineers. In recent decades, the creation of defensive conditions in structures of great importance and very high impact against loads is an integral part of structural designs. In this laboratory research, a mixing plan was made of ordinary concrete containing Portland cement type 2 with a grade of 500 kg/m³. Impact strength test of falling weight in concrete was performed on concrete samples at 90-day curing age at 21, 300 and 600 °C. In order to further evaluate and validate the results, scanning electron microscopy (SEM) and X-ray diffraction (XRD) spectroscopy tests were performed on concrete samples at 90 days of processing age. The results of the tests of this research were evaluated and compared with the results of the research of others. Heat application in concrete samples had a significant effect on the results. In this regard, in the drop weight test, the absorbed energy increased from 269.7214 (at 21 °C) to 41.5956 (at 600 °C) and decreased It had 76.92 percent and the flexibility index increased from 2.3 (at 21 degrees Celsius) to 2.5 (at 600 °C) and improved by 69.8 percent. At the end of this study, the results of SEM and XRD analysis at 21 °C and high temperature, while coordinating with each other, overlapped with the results of other tests in this article.

کلیدواژه‌ها [English]

Ordinary Portland Cement Concrete (OPCC)
Impact Resistance
Drop Weight Test
Scanning Electron Microscopy (SEM)
X-Ray Diffraction (XRD)

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