تحلیل اجزاء محدود و تجربی رفتار پیوستگی بین آرماتور و بتن حاوی الیاف، میکروسیلیس و نانوسیلیس

نوع مقاله: پژوهشی

نویسندگان

دانشگاه حکیم سبزواری

چکیده

رفتار پیوستگی بین آرماتور و بتن به جهت کاربرد روزافزون بتن مسلح در سازه های مختلف از جمله مهم ترین موضوعات مورد بررسی در دنیا می­باشد. در این پژوهش کـه به‌صورت آزمایشگاهی و مدل­سازی اجزاء محدود توسط نرم افزار ABAQUS انجام‌گرفته است، 36 طرح اختلاط بتنی با سه نوع رده مقاومتی سیمان و با درصدهای مختلف الیاف پلیمری، میکروسیلیس و نانوسیلیس ساخته شده و تاثیر این مواد بر رفتار پیوستگی بین آرماتورهای فولادی و بـتن و برخی خـواص مکـانیکی بـتن ازجمله مقاومـت فشـاری آن سنجیده شده است. روش استفاده از فنر غیرخطی نیز جهت مدل­سازی این رفتار پیوستگی ارائه شده و مورد تحلیل دینامیکی غیرخطی واقع شده است.

نتایج حاکی از هماهنگی قابل قبول مدل با نتایج آزمایشگاهی دارد. همچنین نشان می­دهد در این روش به دلیل وجود فنر، نحوه مش بندی المان­ها تاثیر ناچیزی بر نتایج پیوستگی- لغزش خواهد داشت. علاوه بر این، نتایج حاصل از آزمایشات و مقایسه آن با نتایج مدل­سازی نشان می­دهد که تاثیر الیاف در مقاومت پیوستگی ناچیز ولی در نحوه شکست بسیار موثر است. ترکیب توام میکرو و نانوسیلیس نیز می­تواند باعث بهبود مقاومت پیوستگی در حدود 20% گردد به طوری که استفاده از درصدی برابر از این دو ماده بهترین نتایج مقاومت پیوستگی را به دنبال داشته است.

کلیدواژه‌ها


عنوان مقاله [English]

Finite Element and Experimental Analysis of Bond Behavior Between Reinforcement and Concrete Containing Fibers, Silicafume and Nanosilica

نویسندگان [English]

  • Hamid Eskandari
  • Masoud Nematinejad
چکیده [English]

Bond behavior between reinforcement and concrete, due to increasing application of reinforced concrete, is one of the most important issues all over the world. In this research, which has been done experimentally and finite element (FE) modeling (using ABAQUS software), 36 mixtures are deigned considering three cement strength grades and various percentages of polymer fibers, silica fume and nano-silica. The effects of these admixtures on the bond behavior between concrete and reinforcement and also the compressive strength of concrete are investigated. The method of applying nonlinear spring (translator) for finite element modeling is presented and the model is analyzed using nonlinear dynamic analysis. The results yielded acceptable correlation between experimental and FE model. Since there are some translators in model, it can be mentioned that the results of bond slip are not influenced by meshing algorithm. Moreover, comparison of the experimental and FE results showed that while the effect of fiber in bond strength is negligible, it can be so effective in determining the failure shape. The combination of silica fume and nano silica can also improve the bond strength about 20% so that applying equal amount of these two admixtures may leads to the best strength results.

کلیدواژه‌ها [English]

  • Concrete
  • Fibers
  • Silica Fume
  • Nanosilica
  • Bond behavior
  • Finite element modeling
  • nonlinear dynamic analysis
  • Pull-out Test
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