ارزیابی تاثیر میکروسیلیس بر خواص مکانیکی بتن های با سنگدانه های ریز بازیافتی بتنی

نوع مقاله : علمی - پژوهشی

نویسندگان

1 دانشیار، گروه مهندسی عمران، واحد اهواز، دانشگاه آزاد اسلامی، اهواز، ایران

2 دانشجوی دکتری، گروه عمران، واحد اهواز، دانشگاه آزاد اسلامی، اهواز، ایران

چکیده

امروزه کاملا روشن گردیده که سرعت توسعه زیرساخت‌های عمرانی در کشورهای در حال توسعه منجر به وارد آمدن آسیب‌های فراوانی به محیط زیست شده است. بتن یکی از محصولاتی است که نقش زیادی در مصرف منابع تجدیدناپذیر دارد. امروزه نگاه مبتنی بر توسعه پایدار در صنعت ساخت در حال رشد و فزونی است و بتن به عنوان یکی از پرمصرف‌ترین محصولات ساختمانی در صدر این نگاه قرار گرفته است. تحقیق حاضر به بررسی تاثیر استفاده از پودر پوزولان‌ میکروسیلیس بر خواص مکانیکی بتن‌های بازیافتی ساخته شده از سنگدانه‌های ریز بازیافتی بتنی پرداخته است. بتن‌های بازیافتی، متشکل از سطوح مختلف جایگزینی ریزدانه‌های بازیافتی بتنی همراه با ریزدانه‌های طبیعی هستند. جهت بهبود کیفیت بتن‌های بازیافتی، پوزولان معرفی شده در سطوح مختلفی با سیمان جایگزین شد. جهت تعیین و مقایسه خواص مکانیکی بتن‌ها، 12 طرح اختلاط ساخته شده و آزمایش‌های مقاومت فشاری در سنین 7، 28 و 91 روزه، مقاومت کششی دونیم شدن و سرعت امواج فراصوت در سن 28 روزه انجام شدند. نتایج نشان دادند که به طور کلی در بازه 28 روزه، استفاده از میکروسیلیس می‌تواند باعث شود تا بتن‌های %25 بازیافتی به مقاومت مطلوب 40 مگاپاسکالی دست یابند. استفاده از سطح جایگزینی %10 میکروسیلیس، به ویژه در بتن‌های حاوی %25 مصالح بازیافتی، باعث گردید تا خواص مکانیکی بتن‌های بازیافتی به میزان چشم‌گیری به بتن‌های معمولی نزدیک گردند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Evaluation of silica-fume effect on the mechanical properties of concrete with fine recycled aggregates

نویسندگان [English]

  • Seyed Fathollah Sajedi 1
  • Reza Afshar 2
1 Associate Professor, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran
2 Islamic Azad University of Ahvaz
چکیده [English]

Today, it is quite clear that the speed of development of infrastructure in developing countries has led to much damage to the environment. Concrete is one of the products that plays an important role in the use of non-renewable resources. Today, the vision of sustainable development in the manufacturing industry is growing and increasing, and concrete is at the forefront of this as one of the most widely used construction products. The present study investigates the effect of the use of silica-fume (SF) pozzolan powder on the mechanical properties of recycled concrete made from fine recycled aggregates. Recycled concretes consists of different levels of replacement of fine recycled concrete with natural fines. In order to improve the quality of recycled concrete, Pozzolan was introduced at various levels with cement. To determine and compare the mechanical properties of concrete, 12 mixing designs were made and compressive strength tests at 7, 28 and 91 days, tensile strength, and ultrasound velocity at 28 days of age were performed. The results showed that, generally speaking, in the 28-day period, the use of SF can cause 25% recycled concretes to achieve a desirable 40 MPa strength. The use of 10% SF replacement rate, especially in concrete containing 25% recycled aggregates, made the mechanical properties of recyclable concretes significantly closer to conventional concrete.

کلیدواژه‌ها [English]

  • Recycled Concrete
  • Mechanical properties
  • Pozzolan
  • Silica-fume powder
  • Fine recycled aggregates
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