افزایش مقاومت خمشی و انعطاف‌پذیری ماتریس بتن الیافی به روش آزمایشگاهی (با تغییرات حجمی انواع الیاف)

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکده مهندسی عمران، دانشگاه جامع امام حسین (ع)، تهران، ایران

چکیده

با افزودن الیاف و همچنین موادی مضاعف در بتن می‌‌توان خواص بتن از نظر افزایش دوام،  انعطاف‌پذیری و مقاومت کششی را افزایش داد. دیگر کاربرد الیاف مصنوعی به‌منظور بهبود خواص مکانیکی و کاهش جمع‌شدگی بتن تازه و سخت شده، افزایش جذب انرژی و مقاومت در برابر ضربه و انفجار را می‌‌توان اشاره کرد.  استفاده از بتن الیافی مزیت‌‌های زیادی در مقابل استفاده از بتن‌آرمه دارد ضمن آنکه معایبی نیز دارد از جمله عدم توزیع یکنواخت الیاف در ماتریس بتن و عدم چسبندگی مناسب بین الیاف پلیمری در ملات سیمانی است. عموماً از بتن الیافی به دلیل ترک‌‌های کوچک‌‌تر و با عرض کم‌‌تر و دوام بیش‌‌تر در صورت  توزیع یکنواخت الیاف، در قطعات بتنی استفاده می‌‌شود. تحقیقات نشان می‌‌دهد الیاف مقاومت کششی، شکل‌پذیری ملات و بتن را به نحو قابل‌توجهی افزایش می‌‌دهد. در حقیقت الیاف بعد از ترک‌خوردگی در میان صفحات ترک پل می‌‌زند و باعث افزایش چشمگیری در چقرمگی و ظرفیت جذب انرژی می‌‌گردد. اضافه نمودن الیاف مصنوعی به بتن مزیت‌‌هایی چون کاهش ترک‌‌های گیرش پلاستیک، کاهش ترک‌‌های افت پلاستیک، افزایش مقاومت ضربه‌‌ای و افزایش مقاومت در برابر خردشدگی به همراه دارد. در این تحقیق تأثیر انواع  الیاف با درصدهای حجمی مختلف بر مقاومت فشاری، خمشی و کششی نمونه‌‌ها در سن‌‌های مختلف نسبت به نمونه شاهد به روش آزمایشگاهی سنجیده شده است. انواع نمونه‌‌ها را برای حالت تعیین مقاومت در برابر انفجارهای سطحی  مورد آزمایش قرار داده شده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Increasing bending strength and flexibility of fiber concrete matrix by laboratory method (with volume changes of all kinds of fibers)

نویسندگان [English]

  • Ferydoon Khosravi
  • Sayed Mohammad Moayedian
  • Mohammad Fayyaz
  • mahdi dehghannezhad sani abadi
Kheybar Group, Protective Structures department, Jame emam hossein univ., Tehran, Iran
چکیده [English]

By adding fibers as well as additional materials to concrete, the properties of concrete can be increased in terms of durability, flexibility, and tensile strength. Another use of artificial fibers to improve mechanical properties and reduce shrinkage of fresh and hardened concrete, increase energy absorption and resistance to impact and explosion can be mentioned. The use of fiber concrete has many advantages compared to the use of reinforced concrete, while it also has disadvantages, such as the lack of uniform distribution of fibers in the concrete matrix and the lack of proper adhesion between polymer fibers in cement mortar. Generally, fiber concrete is used in concrete parts due to smaller cracks and less width, and more durability in case of uniform distribution of fibers. Research shows that fibers significantly increase the tensile strength and plasticity of mortar and concrete. In fact, after cracking, the fibers bridge between the crack plates and cause a significant increase in toughness and energy absorption capacity. Adding artificial fibers to concrete brings advantages such as reducing plastic grip cracks, reducing plastic drop cracks, increasing impact resistance, and increasing resistance to crushing. In this research, the effect of different types of fibers with different volume percentages on the compressive, bending, and tensile strength of the samples at different ages compared to the control sample has been measured by the laboratory method. All kinds of samples have been tested to determine the resistance against surface explosions.

کلیدواژه‌ها [English]

  • Fiber concrete
  • polymer fibers
  • increasing the tensile strength of concrete
  • steel fibers
  • laboratory method
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