بررسی ویژگی‌های مکانیکی بتن ژئوپلیمری و کاربرد آن در اتصال تیر به ستون

نوع مقاله : مقاله پژوهشی

نویسندگان

دانشکدهی مهندسی عمران و حمل و نقل، دانشگاه اصفهان، اصفهان، ایران.

چکیده

با توجه به تأثیر مواد قلیایی بر ویژگی‌های مکانیکی بتن ژئوپلیمری بر پایه‌ی سرباره، تأثیر غلظت محلول هیدروکسید سدیم و تأثیر نسبت وزنی هیدروکسید سدیم به سیلیکات سدیم بر مقاومت فشاری، مقاومت کششی و مدول الاستیسیته‌ی بتن ژئوپلیمری در این پژوهش بررسی شده است. بدین منظور شش طرح اختلاط در نظر گرفته شد. نتایج حاصل از آزمایش‌ها نشان دادند، با کاهش نسبت هیدروکسید سدیم به سیلیکات سدیم و افزایش غلظت هیدروکسید سدیم مقاومت فشاری و مقاومت کششی بتن افزایش می‌یابد. همچنین با افزایش غلظت هیدروکسید سدیم و کاهش نسبت هیدروکسید سدیم به سیلیکات سدیم، مدول الاستیسیته کاهش می‌یابد. بنابراین طرحی با نسبت هیدروکسید سدیم به سیلیکات سدیم برابر 0/4 و غلظت 6 مولار هیدروکسید سدیم به علت دارا بودن بیش‌ترین مقاومت فشاری به عنوان بهترین طرح در این پژوهش انتخاب شد. بررسی‌های انجام شده بر روی آثار زلزله‌های متعدد نشان داده است که اتصال‌های تیر به ستون بتنی در قاب‌های خمشی یکی از نقاط ضعیف و یکی از عوامل اصلی تخریب آن‌ها هستند. در مرحله‌ی دوم این پژوهش دو نمونه اتصال تیر به ستون یکی با بتن ژئوپلیمری با طرح بهینه و دیگری با بتن معمولی ساخته شد؛ سپس به منظور بررسی رفتار چرخه‌ای اتصال، آزمایش طبق پروتکل بارگذاری آیین‌نامهACI 374.1-05  انجام گردید. نتایج حاصل از آزمایش نشان داد اتصال تیر به ستون کناری با استفاده از بتن ژئوپلیمری، بر اساس معیارهای پذیرش آیین‌نامه‌ی ACI 374.1-05 رفتار مناسب و عملکرد لرزه‌ای رضایت‌بخشی به همراه تشکیل مفصل پلاستیک در تیر داشته است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation of Mechanical Properties of Geopolymer Concrete and Its Application in Beam-Column Joint

نویسندگان [English]

  • tayebe yousefi
  • Hossein Tajmir Riahi
master of sience student
چکیده [English]

In this study, the effects of sodium hydroxide solution concentration and sodium hydroxide to sodium silicate weight ratio on compressive strength, tensile strength, and elastic modulus of slag-based geopolymer concrete are investigated. The results of the experiments show that by reducing the ratio of sodium hydroxide to sodium silicate and increasing the concentration of sodium hydroxide, the compressive strength and tensile strength of concrete increase. In addition, by increasing the concentration of sodium hydroxide and reducing the ratio of sodium hydroxide to sodium silicate, the modulus of elasticity decreases, and no clear relationship is observed between compressive strength and modulus of elasticity of geopolymer concrete. Therefore, a mix design with a ratio of sodium hydroxide to sodium silicate equal to 0.4 and a concentration of 6 molarity sodium hydroxide with the highest compressive strength was selected to be used for the second step of the research. The performance of beam-column joints in past earthquakes shows their importance in the performance of concrete moment-resisting frames. Therefore, in the second step of this research, an experimental study is done for two beam-column joints with geopolymer concrete and ordinary concrete. In order to investigate the cyclic behavior of the joint, the experiment is performed according to the loading protocol of ACI 374.1-05. The results of the experiment show that the geopolymer concrete beam-column joint has the acceptance criteria of ACI 374.1-05 regulations, and also, its seismic performance assures that the plastic hinge is generated in the beam properly.

کلیدواژه‌ها [English]

  • Geopolymer concrete
  • Concrete beam-column joint
  • Cyclic behavior
  • Mix design
  • Alkaline solutions
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