نوع مقاله: مقاله پژوهشی

نویسندگان

1 مدرس حق التدریس

2 دانشجوی دانشگاه شهاب دانش

3 عضو هیات علمی مرکز تحقیقات راه، مسکن و شهرسازی

4 مدیر واحد تحقیق و توسعه شرکت دانش بنیان نانو بتن امین

10.30478/jcsm.2019.153789.1093

چکیده

انتقال رطوبت و یون‌های مخرب همراه با آن ازجمله عوامل اصلی تهدیدکننده دوام سازه‌های بتنی می‌باشند. افزودنی‌های نم بند مانند استئارات کلسیم می‌توانند با ایجاد یک‌لایه آب‌گریز در سطح منافذ مویینه، ورود آب به داخل بتن را محدود کرده و بدین طریق دوام سازه‌های بتنی را بهبود بخشند. بر این اساس، در این پژوهش اثر استئارات کلسیم بر مشخصات بتن خودتراکم در حالت‌های تازه و سخت‌شده بررسی شده است. نتایج این مطالعه نشان می‌دهد که در حالت بتن تازه، چگالی، قابلیت پرکنندگی و قابلیت عبور بتن خودتراکم در صورت استفاده از این افزودنی کاهش می‌یابد، اما این ماده بر افت اسلامپ بتن خودتراکم اثر محسوسی نمی‌گذارد. یافته‌های پژوهش در بخش مشخصات مکانیکی حاکی از کاهش در مقاومت فشاری و چگالی بتن سخت‌شده می‌باشد. نهایتاً، بررسی پارامترهای دوامی نشان می‌دهد که گرچه این مواد تأثیر قابل‌ملاحظه‌ای بر مقاومت الکتریکی، جذب آب کلی و ضریب مهاجرت تسریع‌شده یون‌های کلراید نمی‌گذارند، اما استفاده این مواد، جذب آب مویینه و جذب آب حجمی را به‌شدت کاهش می‌دهد؛ بطوریکه، در صورت استفاده از 7 کیلوگرم بر مترمکعب استئارات کلسیم، عمق نهایی نفوذ مویینه، جذب آب نیم‌ساعته و سه‌روزه را به ترتیب 60%، 65% و 13% کاهش می‌یابند.

کلیدواژه‌ها

عنوان مقاله [English]

Influence of calcium stearate on the properties of self-consolidating concretes

نویسندگان [English]

  • ramin naseroleslami 1
  • Javad Bakhshi 2
  • Mehdi Nemati Chari 3
  • Mojtaba Hajmahdi 4

1 College teacher

2 Student of Shahab danesh university

3 Faculty member Concrete Technology Department; Road, Housing & Urban Development Research Center (BHRC)

4 Director of Research and Development Unit of Knowledge Foundation of Amino Nanotechnology

چکیده [English]

 
 
Moisture and water transfer into concrete can be considered as a major threat to the durability of concrete. Damp-proofing admixtures like calcium stearate (CS) can provide a water repellent layer along the capillary pores. As a result, water and moisture transfer into concrete will be restricted by means of this layer. Accordingly, this research studied the effects of CS on the properties fresh and hardened self-consolidating concrete (SCCs). The evaluation of fresh concrete properties demonstrated that the density of fresh SCCs, passing and filling ability were reduced due to incorporation of CS. Moreover, reduction in density and compressive strength of the hardened concrete can be deemed as the major impacts of CS on mechanical properties of SCCs. In fact, the last-mentioned parameters were decreased by respectively 4% and 30% due to inclusion of 7kg/m3 CS. Furthermore, utilizing CS can not be taken into account as a constructive approach to improve the durability chracteristics under hydrostatic condition. Because no considerable improvement can to be detected in the results of electrical resistivity and rapid chloride migration tests. Eventually, CS drastically enhanced the permeability of the concrete under non-hydrostatic condition. To be more precise, addition of   7kg/m3   of CS decreased the final depth of capillary water absorption, short and long-term water absorption by respectively 60%, 65% and 15%.
 

کلیدواژه‌ها [English]

  • : calcium stearate
  • damp-proofing admixtures
  • Durability
  • Self-consolidating concrete
  • water absorption

1.      

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]28[ بتن- اندازه گیری جریان اسلامپ بتن خودتراکم- روش آزمون- استاندارد ملی INSO 11270

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]30 [آزمون بتن تازه- بتن خودتراکم- آزمون قیف وی شکل- استاندارد ملی INSO 3203-9

]31 [بتن تازه- وزن مخصوص- روش آزمون- استاندارد ملی ISIRI 3203-6

]32 [بتن سخت شده- تعیین مقاومت فشاری آزمونه ها- روش آزمون- استاندارد ملی  INSO 1608-3

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]37 [سنگدانه های بتن- ویژگی ها- استاندارد ملی 302  تجدید نظر سوم-INSO 302