ارزیابی آزمایشگاهی مقاومت باند بین میلگرد و بتن حاوی پودر سنگ آهک

نوع مقاله : مقاله پژوهشی

نویسندگان

1 گروه عمران، دانشکده صنعت و معدن چرام، دانشگاه یاسوج، چرام، ایران

2 گروه مهندسی عمران، دانشکده مهندسی معدن عمران و شیمی، دانشگاه صنعتی بیرجند، بیرجند ایران

چکیده

مقدار چسبندگی بین بتن و میلگردهای مسلح کننده نقش تعیین کنندهای در رفتار سازه‌های بتن مسلح و ً توسط پیوستگی همچنین مود شکست آنها دارد. این چسبندگی که تحت عنوان مقاومت باند شناخته می‌شود، اکثرا مهاری تامین می‌شود و می‌تواند به واسطة تغییر ترکیبات بتن دستخوش تغییر گردد. مقاله حاضر به ارزیابی آزمایشگاهی مقاومت باند بین میلگرد و بتن حاوی پودر سنگ آهک پرداخته است. برای این منظور، مقادیر 5 ،15 و 30 درصد سیمان نمونه بتنی شاهد (بدون پودرسنگ آهک) با سنگ آهک جایگزین شده و مقدار مقاومت باند به همراه مقاومت فشاری برای نمونه‌ها در سنین 7 ،28 و 90 روزه بدست آمده است. دراین تحقیق از نمونه‌های مکعبی با ابعاد 15 سانتی‌متر و میلگرد با قطر 16 میلی‌متر برای ارزیابی باند استفاده شده است. نسبت آب به سیمان ثابت و برابر با 0/4 در نظر گرفته شده است. همچنین مقدار مقاومت باند بین بتن و میلگرد از طریق آزمایش بیرون کشیدن میلگرد محاسبه شده است. نتایج کلی نشان می‌دهند که مقاومت باند با افزایش درصد سنگ آهک در بتن کاهش می‌یابد، مقدار این کاهش برای نمونه با 5 درصد پودر ً 40 درصد بدست آمده است. همچنین سنگ آهک کمتر از 10 درصد و برای نمونه با 30 درصد پودر سنگ آهک تقریبا ارزیابی مدل‌های موجود برای پیش بینی مقاومت باند نشان می‌دهد که این مدل‌ها مقاومت باند بزرگتری نسبت به نتایج آزمایشگاهی ارائه می‌دهند که در جهت خلاف اطمینان است. لذا ارائه یک مدل مناسب برای تخمین مقاومت باند نمونه‌های بتنی حاوی پودرسنگ آهک ضرورت می‌یابد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Laboratory Evaluation of Bond Strength Between Rebar and Concrete Containing Limestone Powder

نویسندگان [English]

  • Seyed Abbas Hosseini 1
  • Sadegh Etedali 2
1 Faculty of Technology and Mining, Yasouj University, Choram, Iran
2 Department of Civil Engineering, Birjand University of Technology, Birjand, Iran
چکیده [English]

The amount of adhesion between the concrete and the reinforcing bars plays a decisive role in the behavior of the RC structures, as well as their failure mode in the final extreme cases. This adhesion, known as band resistance, can be altered by changing the concrete mix. Laboratory evaluation of bond strength between rebar and concrete containing limestone powder is carried out in the present paper. For this purpose, 5, 15 and 30% of the cement of the control specimen (without limestone powder) is replaced with limestone powder and bond and compressive strength are obtained for specimens at the age of 7, 28 and 90 days. In this study, 15 cm concrete cubic and 16 mm diameter rebar are used to evaluate the bond. The water to binder ratio (w/b) is fixed at 0.4. Also, the test of pulling out the rebar is applied to calculate the bond strength between the concrete and steel reinforcement. The overall results show that the bond strength decreases with the increasing percentage of limestone in concrete, the amount of this reduction is less than 10% for a sample with 5% limestone powder, while a reduction about 40% is obtained for a sample with 5% limestone powder. The assessment of the exciting models for prediction the bond strength indicates that these models estimate a bond strength larger than those given by the experimental results. Therefore, it is necessary to provide a suitable model for estimating the bond strength of concrete containing limestone powder.

کلیدواژه‌ها [English]

  • Concrete technology
  • Bond Strength
  • Limestone Powder
  • Pull Out Test
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