ارائه مدل تجربی تاثیر تغییرات ابعاد نمونه بتنی مسلح به الیاف ماکروسینتتیک بر انرژی شکست

نوع مقاله : علمی - پژوهشی

نویسندگان

1 استاد و عضو هیئت علمی دانشکده عمران و محیط زیست دانشگاه تربیت مدرس, تهران, ایران

2 دانشکده عمران و محیط زیست دانشگاه تربیت مدرس

چکیده

بتن به عنوان یکی از پرکاربردترین مصالح ساختمانی رفتاری شکننده دارد. افزودن الیاف به بتن بر رفتار شکل‌پذیری و برخی مشخصات مکانیکی بتن اثر میگذارد. به همین منظور پژوهشی آزمایشگاهی جهت ارائه مدل تجربی تاثیر اندازه نمونه بتن مسلح به الیاف ماکروسینتتیک بر تغییرات انرژی شکست انجام شد. در این پژوهش نمونه‌های تیرچه بتنی به صورت بتن معمولی و بتن مسلح به الیاف ماکروسینتتیک و با سه ضخامت و سه عرض مختلف ساخته شده، انرژی شکست نمونه‌ها اندازه‌گیری و نتایج مورد تجزیه و تحلیل قرار گرفته اند. نتایج نشان داد که با افزایش ضخامت نمونه، مقدار انرژی شکست به میزان 1/63-3/15 درصد و همچنین با افزایش عرض نمونه، انرژی شکست به میزان 72/50-04/42 درصد افزایش می یابد.
بتن الیافی یکی از انواع بتن می باشد که با الیاف ترکیب شده است. الیاف مختلفی برای تهیه بتن الیافی استفاده می شود مانند الیاف شیشه، پلیمری، کربن و فولاد. در این پژوهش از الیاف پلیمری ماکروسینتتیک استفاده شد. از کاربرد های الیاف ماکروسینتتیک در بتن میتوان به کاهش میزان جمع شدگی بتن تازه و سخت، افزایش شکل پذیری، ضربه پذیری و سختی بتن، افزایش مقاومت در برابر تنش های خستگی، افزایش دوام و طول عمر بتن ، بهبود ویژگی های مکانیکی بتن (مقاومت کششی، خمشی و...)، کنترل ترک های ثانویه/حرارتی بتن، جلوگیری از گسترش ترک ها به عمق، قابلیت بارپذیری پس از ایجاد ترک، کاهش نفوذپذیری در مقابل یون های کلر و سولفات. پژوهش های متعددی در زمینه بتن الیافی انجام گرفته است. در این پژوهش با استفاده از مفهوم مکانیک شکست مدل های انرژِی تغییر ضخامت ارائه شد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Presenting an experimental model to investigate the effect of changing the dimensions of macro-synthetic-fiber-reinforced concrete on fracture energy

نویسندگان [English]

  • abolfazl hassani 1
  • mohammad daneshfar 2
1 school of civil and environment , tarbiat modares university, tehran, iran.
2 school of civil and environment, tarbiat modares university
چکیده [English]

Concrete has a brittle behavior as one of the most frequently used construction materials. Adding fibers to concrete can enhance its ductility and some of its mechanical properties. For this purpose, a laboratory study was conducted in order to present an experimental model to investigate the effect of size of micro-synthetic-fiber-reinforced concrete on fracture energy changes. In this study, concrete beam specimens were manufactured and evaluated with three different thicknesses and widths. Results indicated that by increasing the thickness of the specimens, fracture energy was respectively increased by 15.3-63.1%. Moreover, by increasing the width of the specimen, fracture energy was respectively increased by 42.04-50.72 %.
Fiber-reinforced concrete is a type of concrete that is mixed with fiber. Various types of fibers are used to produce fiber-reinforced concrete, which include glass, polymer, carbon and steel .
In the present research, macro-synthetic polymer fibers were used. Some of the consequences of applying macro-synthetic fibers in concrete include reduced shrinkage of fresh and hardened concrete, increased ductility, vulnerability and hardness of concrete, increased strength against fatigue stresses, increased durability and lifetime of concrete, improved concrete mechanical properties (tensile strength, flexural strength, etc.), control of secondary/thermal cracks of concrete, preventing the in-depth propagation of cracks, post-cracking chargeability and reduced permeability against chloride and sulfate ions . To date, numerous studies have been conducted on fiber-reinforced concrete, most of which have been focused on the evaluation of fiber-reinforced concrete using steel and plastic fibers or their combination.

کلیدواژه‌ها [English]

  • fiber-reinforced concrete
  • macro synthetic
  • fracture energy
  • flexural toughness
  • concrete beam

مراجع

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سابقه مقاله

  • تاریخ دریافت: 29 بهمن 1396
  • تاریخ بازنگری: 04 تیر 1397
  • تاریخ پذیرش: 16 مرداد 1397

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