مطالعه تجربی و ارزیابی عددی مشخصات حرارتی بتن حجیم خودتراکم

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشیار دانشکده مهندسی، دانشگاه بوعلی سینا

2 دانشجوی دکترای عمران گرایش سازه، دانشگاه بوعلی سینا همدان

چکیده

استفاده از بتن در سازه‌های خاص همواره با چالش‌هایی در اجرا مواجه است. در اعضای حجیم بتن مسلح با تراکم زیاد میلگرد استفاده از بتن خودتراکم باعث سهولت اجرا خواهد شد. از طرف دیگر افزایش مقدار سیمان جهت افزایش مقاومت،گرادیان حرارتی بین سطح و مرکز تنش حرارتی را افزایش خواهد داد و لذا شناخت رفتار حرارتی این بتن و ارزیابی ترک‌ خوردگی ضروری است. در این مقاله مطالعه آزمایشگاهی مشخصات حرارتی و مکانیکی بتن خودتراکم حجیم و تحلیل تنش حرارتی انجام گرفته است. نتایج حاکی از آن است که به ‌منظور کاربرد بتن خودتراکم در المان‌های حجیم پرمقاومت، این بتن در مقایسه با بتن معمولی علاوه بر مشخصات مکانیکی مطلوب‌تر در سطح و مرکز بتن حجیم، رژیم حرارتی متفاوت و مناسب‌تری داشته است. مقدار کرنش کمتر و افزایش زمان رخداد تبدیل تنش منجر به کاهش تنش حرارتی شده و در نهایت ریسک ترک‌ خوردگی تا سی‌و‌شش درصد کاهش یافته است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Experimental study and numerical evaluation of self-compacting mass concrete thermal properties

نویسندگان [English]

  • M. Nili 1
  • amir hosein ghorbankhani 2
1 Associate professor, Civil Eng., Dept., Bu-Ali Sina University, Hamedan, I.R.Iran
2 PHD Candidate, BualiSina University, Hamadan
چکیده [English]

The use of concrete in special structures always faces challenges in implementation. By increasing the amount of cement to increase the compressive strength, the thermal gradient between the surface and the center of the concrete due to hydration heat will lead to an increase in thermal stress. On the other hand, due to the highly congested rebars in massive structural members of reinforced concrete such as columns of high-rise structures, the use of self-compacting concrete will facilitate the implementation and therefore understanding the thermal behavior of concrete and comparing it with ordinary concrete can be a good ground for studying crack risk. In this paper, the evaluation of thermal and mechanical properties affected by the application of high strength self-compacting mass concrete regime with three ratios of water to cement ratio and two cement content has been done in the form of twelve mixed designs. The results show that self-compacting concrete in addition to better mechanical properties on the surface and core of high strength mass concrete had different and more suitable thermal regime compared to ordinary concrete. Its lower strain and higher stress conversion time reduces thermal stress and ultimately reduces the risk of cracking up to thirty-six percent.

کلیدواژه‌ها [English]

  • Mass concrete
  • Self-compacting
  • Modulus of elasticity
  • Thermal regime
  • Risk of cracking
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