بررسی اثر نانوسیلیس بر مقاومت فشاری و خمشی ملات سیمان تقویت‌شده با الیاف پلی‌پروپیلن

نوع مقاله : علمی - پژوهشی

نویسندگان

1 کارشناس ارشد/دانشگاه آزاد اسلامی واحد تاکستان

2 استادیار آزاد تاکستان

3 استادیار

چکیده

ملات ماده‌ای است که به دلیل دارا بودن مقاومت فشاری قابل توجه، کاربردش در قطعات تحت فشار مانند ستون‌ها و قوس‌ها بسیار مناسب است. لیکن علی‌رغم مزیت مذکور، مقاومت کششی کم و شکنندگی نسبتاً زیاد ملات استفاده از آن را برای قطعاتی که تماماً یا به طور موضعی تحت کشش هستند محدود می‌نماید. بهره‌گیری از الیاف می‌تواند راهکاری در راستای ممانعت از این نقایص باشد. اما ضعف پیوند ماتریس و الیاف می‌تواند به عنوان مانعی مطرح باشد. لذا افزودن نانوذرات می‌تواند در جهت رفع این مشکل استفاده گردد. در این تحقیق، نمونه‌های ملات سیمان تقویت شده با الیاف و حاوی نانوسیلیس تهیه گردید تا تأثیر نانوذرات سیلیس بر روی خواص مکانیکی ملات حاوی الیاف پلی‌پروپیلن و همچنین فاقد این الیاف مورد ارزیابی قرار گیرد. الیاف پلی‌پروپیلن مصرفی دارای طول 18-6 میلی‌متر و نسبت طول به قطر 900-300 بودند. تأثیر الیاف در دو درصد مختلف 1/0% و 2/0% و تأثیر نانوسیلیس در درصدهای متفاوت 1، 2 ، 3، 4 و 5% روی ملات با نسبت آب به سیمان 485/0 مورد مقایسه و بررسی قرار گرفت. در مجموع 108 نمونه مکعبی به ابعاد cm3 5×5×5 و همچنین 108 نمونه مکعب‌مستطیلی به ابعاد cm3 4×4×16 براساس استانداردهای ASTM ساخته شد و آزمایش‌های مقاومت فشاری و مقاومت خمشی در سنین 7 و 28 روز بر روی نمونه‌ها انجام پذیرفت. نتایج حاصل از آزمایشات بیانگر افزایش قابل توجهی در مشخصات مکانیکی ملات‌های حاصله بود؛ به طوریکه استحکام فشاری 7 روزه نمونه حاوی 1/0% الیاف و 3% نانوسیلیس نسبت به طرح شاهد حدود 51% و استحکام فشاری 28 روزه آن حدود 61% افزایش نشان داد. همچنین استحکام خمشی 7 روزه نمونه حاوی 2/0% الیاف و 3% نانوسیلیس نسبت به طرح شاهد حدود 48% و استحکام خمشی 28 روزه آن حدود 55% افزایش نشان داد. افزایش چشم‌گیر خواص مکانیکی نشان از عملکرد مناسب این نوع ملات دارد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Investigation of the Effect of Nano-Silica on the Compressive and Flexural Strength of Cement Mortar Reinforced with Polypropylene Fibers

نویسندگان [English]

  • meisam fazlavi 1
  • hosein mehdikhani 2
  • saeed maadani 3
1 azad takestan
2 Assistant Professor
3 Assistant Professor
چکیده [English]

Mortar is suitable for utilizing in compressed parts such as columns and arches due to its considerable compressive strength. However, despite this advantage, the relatively low tensile strength and brittleness of the mortar limit its use for components that are under tensile loads. Using fibers and nano-particles can be a way to reduce these problems. In this research work, various fiber reinforced and nano-engineered cement mortars have been successfully prepared through the addition of nanosilica into plain and fiber reinforced mortars. In this way, effects of nano-SiO2 on the mechanical properties of cement mortars with polypropylene fibers and also without it have been evaluated. Polypropylene fibers were used in lengths of 6-18 mm and aspect ratios of 300-900. The effect of fibers in two different percentages of 0.1% and 0.2%, and the influence of nano-silica in various percentages of 1, 2, 3, 4 and 5% on mortars with a water-to-binder weight ratio of 0.485 were evaluated and compared. A total of 108 cubic mortar samples with a dimension of 5×5×5 cm3 and 108 rectangular cubic samples with a dimension of 16×4×4 cm3 were made according to ASTM standards, and compressive and flexural strength tests were carried out on samples at the ages of 7 and 28 days. The results of the experiments indicated a significant enhancement in the mechanical properties of the prepared mortars, as the values of 7-day and 28-day compressive strength of the sample containing 0.1% fiber and 3% nano-SiO2 were increased by 51% and 61%, respectively, compared to the control sample. Besides, the values of 7-day and 28-day flexural strength of the sample containing 0.2% fiber and 3% nano-SiO2 were increased by 48% and 55%, respectively, compared to the control sample. A noticeable increase in mechanical properties indicated the suitable performance of this type of mortar.

کلیدواژه‌ها [English]

  • Fiber Reinforced Mortar
  • Nanomaterials
  • Silica Nanoparticles
  • Compressive strength
  • Flextural Strength
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