بررسی درصدهای مختلف الیاف فلزی جهت بهبود مشخصات مکانیکی و دوام بتن در دماهای بالا

ایزدی فرد, رمضانعلی; عبدی مقدم, مهرداد

doi:10.22065/jsce.2019.166490.1757

بررسی درصدهای مختلف الیاف فلزی جهت بهبود مشخصات مکانیکی و دوام بتن در دماهای بالا

نوع مقاله : علمی - پژوهشی

نویسندگان

¹ گروه مهندسی عمران- دانشکده فنی مهندسی- دانشگاه بین المللی امام خمینی (ره)- قزوین- ایران

² دانشجوی دکتری سازه، دانشگاه بین المللی امام خمینی (ره)، قزوین، ایران

10.22065/jsce.2019.166490.1757

چکیده

یکی از عوامل آسیب و تخریب سازه‌های بتنی آتش سوزی میباشد. سازه‌های بتنی علاوه بر داشتن مشخصات مکانیکی مناسب، میبایست خواص دوام قابل قبولی نیز داشته باشند تا در طول عمر مفید سازه از ظرفیت خود استفاده نمایند. در این مطالعه تاثیردرصدهای حجمی مختلفی از الیاف فلزی در بهبود مشخصات مکانیکی و دوام بتن در دماهای مختلف بررسی شده است. مشخصات مکانیکی شامل مقاومت فشاری و مقاومت کششی بتن در حالت داغ و مشخصات دوام بتن حرارت دیده شامل جذب آب سطحی، عمق نفوذ آب، مقاومت الکتریکی و افت وزنی در آزمایشگاه بررسی شده اند. این مطالعه مقادیر 0.25 و 0.50 درصد حجمی الیاف فلزی و دماهای 28 تا 800 درجه سانتیگراد را پوشش میدهد. نتایج نشان داده است که افزایش مقاومت فشاری و کششی ناشی از افزایش سن نمونه ها، در بتن الیافی بیش از بتن بدون الیاف بوده است. همچنین ملاحظه گردید که افزودن الیاف فلزی به میزان 0.25 و 0.5 درصد حجمی مقاومت فشاری را به در محدوده 10 تا 27 درصد و مقاومت کششی را در محدوده 8 تا 200 درصد در دماهای بررسی شده بهبود داده است. از طرف دیگر کاربرد الیاف فلزی در بتن توانسته است موجب کاهش جذب آب سطحی، عمق نفوذ آب و مقاومت الکتریکی بتن شده و از افت وزنی بتن ناشی از حرارت بکاهد. جمع بندی نتایج این مطالعه نشان داده است که در دماهای کم‌تر و بیش‌تر از 500 درجه سانتیگراد، به ترتیب افزودن 0.25 و0.5 درصد حجمی الیاف بهترین عملکرد را در بهبود مشخصات مکانیکی و دوام بتن معمولی داشته‌است.

کلیدواژه‌ها

موضوعات

مهندسی سازه و آتش

عنوان مقاله [English]

Evaluation of various content of steel fibers on improving the mechanical and durability properties of concrete at high temperatures

نویسندگان [English]

Ramezan Ali Izadifard ¹
Mehrdad abdi moghadam ²

¹ Civil Eng. Dep.- Engineering Faculty- Imam Khomeini Int. Un.- Qazvin- Iran

² 1- PhD candidate, Department of civil engineering, Imam Khomeini International University, Qazvin, Iran.

چکیده [English]

One of the factors of damage and destruction of concrete structures is fire. Concrete structures, in addition to having the proper mechanical characteristics, they must have durability properties to use their capacity over their lifetime. In this study, the effect of various volume fraction of steel fibers on improving the mechanical and durability properties of concrete at various temperatures has been investigated. Mechanical properties including compressive and tensile strength of concrete in the hot condition and the durability characteristics of the concrete after cooling, including surface water absorption, the penetration depth of water, electrical resistance and weight loss have been investigated. This study covers 0.25 and 0.50% volume fraction of steel fibers and temperatures of 28 to 800 ° C. The results show that the increase in compressive strength and tensile strength due to the age of the samples was higher in fiber concrete than non-fibrous concrete. It was also observed that the addition of 0.25 and 0.5% of steel fibers at the tested temperatures improved the compressive and tensile strength in the range of 10 to 27% and 8 to 200%, respectively. In addition, application of these fibers has reduced the sorptivity coefficient, the penetration depth of water, the electrical resistance of concrete and the weight loss of concrete owing to the high temperature. The results of this study showed that, at temperatures below 500 °C specimens containing 0.25% of steel fiber and 500 °C onwards, specimens containing 0.50% of steel fiber had the best performance on the improvement of the mechanical and durability properties of normal concrete at high temperatures.

کلیدواژه‌ها [English]

"Mechanical Properties"
"Durability specifications"
"Steel fiber"
"Concrete"
"High temperatures"

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