اثر مقدار و چند نوع مختلف افزودنی های معدنی بر تغییرات تنش جاری و ویسکوزیته پلاستیک بتن خودتراکم

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشیار، دانشکده مهندسی عمران، دانشگاه علم و صنعت ایران

2 استادیار، دانشکده مهندسی عمران، دانشگاه علم و صنعت ایران

3 دانشجوی کارشناسی ارشد مهندسی و مدیریت ساخت، دانشگاه علم و صنعت ایران

چکیده

در این تحقیق، بتن های خودتراکم با مقادیر متفاوت پودر سنگ آهک و مقدار و نوع افزودنی های مختلف ساخته شده و آزمایش های کارایی و مؤلفه های رئولوژی مخلوطها بررسی شدند. بر این اساس، مخلوط هایی با نسبت آب به سیمان متفاوت و مقادیر مختلف پودر سنگ آهک و سیمان با جایگزینی میکروسیلیس، سرباره و متاکائولن ساخته شده است. لازم به ذکر است که نتایج به دست آمده منحصر به آزمایش های انجام شده در تحقیق حاضر است. نتایج نشان می دهند که افزایش نسبت آب به سیمان موجب کاهش هر دو مؤلفه می شود و از طرفی دیگر، افزایش در مقدار پودر سنگ آهک منجر به کاهش تنش جاری مخلوطها می گردد. در حال یکه ویسکوزیته پلاستیک تا 150 کیلوگرم بر متر مکعب پودر سنگ کاهش و سپس افزایش را نشان می دهد. با جایگزینی 8 درصد میکروسیلیس، تنش جاری افزایش یافت و ویسکوزیته پلاستیک تغییری نکرد؛ در حالی که متاکائولن موجب افزایش هر دو مؤلفه و جایگزینی سرباره تا 15 درصد موجب افزایش تنش جاری شد. اما تغییری در ویسکوزیته پلاستیک ایجاد نگردید. تنش جاری (استاتیکی و دینامیکی) با گذشت زمان افزایش می یابد که این افزایش در زمان های سکون بیشتر، برجسته تر است؛ در حالی است که گذشت زمان بر ویسکوزیته پلاستیک تأثیر چندانی نداشته و مستقل از زمان تغییر می کند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

The effect of amount and several different types of mineral admixtures on the yield stress and plastic viscosity of self-consolidating concretes

نویسندگان [English]

  • P. Ghoddousi 1
  • A. A. Shirzadi-Javid 2
  • M. Lotfi 3
1 Associate Professor, Iran University of Science and Technology (IUST)
2 Assistant Professor, Iran University of Science and Technology (IUST)
3 M.Sc. in Construction and Engineering Management, Iran University of Science and Technology (IUST)
چکیده [English]

The aim of this study was to evaluate the effect of self-consolidating concrete mixture components
on yield stress (static and dynamic yield stress) and plastic viscosity. Accordingly, mixtures with
different water-cement ratio and the amount of limestone powder (100, 150 and 200 kg/m3) were made.
In addition, cement has been replaced with different percentages of silica fume, slag and metakaolin.
Results show that increase in water to cement ratio cause decrease in yield stress and plastic viscosity.
On the other hand, increasing in limestone content leads to yield stress reduction. Over time, this yield
stress increased while the plastic viscosity of mixtures showed no significant change. By replacing the
silica fume, yield stress increased but plastic viscosity unchanged while metakaolin cause increasing in
both parameters.

کلیدواژه‌ها [English]

  • self-consolidating concrete
  • Yield Stress
  • Plastic Viscosity
  • Mineral Admixtures
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