مدل‌سازی عددی نفوذپذیری بتن مسلح به گرافن‌‌اکساید با استفاده از رویکرد تحلیل چندمقیاسی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه بین المللی امام خمینی

2 دانشگاه بین‌المللی امام خمینی (ره)، قزوین، ایران

چکیده

     نفوذپذیری را می ­توان از عوامل مهم و تأثیرگذار بر دوام بتن دانست. در این مطالعه، از نانوذرات گرافن­اکساید (GONPs)(Banthia, 2005 #2) به منظور کاهش حجم نفوذ آب در بتن استفاده شده است. GONPs محصول لایه ­برداری شیمیایی گرافیت بوده و شامل طیف وسیعی از گروه ­های عاملی اکسیژن فعال می ­باشند. در این پژوهش به منظور مطالعه­ ی خواص انتقال بتن غیراشباع تقویت شده با GONPs از رویکرد تحلیل چند­مقیاسی استفاده شده است. در مقیاس نانو، پارامترهای انتقال در کلسیم سیلیکات هیدراته ­ی تقویت شده با GONPs از طریق شبیه­ سازی دینامیک مولکولی (MD) تعیین می ­شوند. در مقیاس میکرو مدل ­سازی سیمان هیدراته انجام گرفته و مشخصه­ های نفوذپذیری آن مشخص می­ شود. در آخر و در مقیاس مزو، یک مدل سه فازی از بتن شامل سنگدانه، خمیر سخت­ شده ­ی سیمان و ناحیه ­ی انتقال بین دو سطح (ITZ) مدل­ سازی شده تا شبیه ­سازی جریان اشباع ­نشده تحت اثرات توأم مکش موئینه، فشار هیدرواستاتیک خارجی و گرانش انجام گیرد. به منظور صحت ­سنجی و تأیید قابلیت اطمینان مدل چند­مقیاسی، نتایج عددی با داده ­های آزمایشگاهی انجام گرفته در این مطالعه جهت پیش­ بینی خواص انتقال آب در بتن اشباع نشده مقایسه شدند. مقایسه­ ی نتایج آزمایشگاهی و عددی نشان داد که روش پیشنهادی می­ تواند پیش ­بینی قابل قبولی از پارامترهای نفوذپذیری در بتن را ارائه دهد. نتایج مدل­ سازی عددی نیز نشان داد که اختلاط درصد بسیار کمی از GONPs ها می­ تواند به طور مؤثری از ورود مولکول­ های آب به بتن جلوگیری کند. درواقع با افزودن GONPs خواص انتقال بتن ارتقاء یافته که متعاقباً دوام آن نیز بهبود می­ یابد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Numerical study on water penetration in graphene oxide reinforced concrete by the multiscale approach

نویسندگان [English]

  • mahna safarkhani 1
  • Mahmood Naderi 2
1 Imam Khomeini International University
2 Department of civil engineering, Faculty of engineering, International Imam Khomeini university, Qazvin, Iran
چکیده [English]

Durability is an important property that determines the long-term behavior of cement-based materials. In this study, graphene oxide nanoparticles (GONPs) are proposed to prevent water ingress into the concrete. GONPs contain a range of reactive oxygen functional groups that enable them as a suitable candidate for reaction in cementitious materials. The multiscale approach is adopted to study the unsaturated transport properties of GONPs-reinforced concrete. At the nanoscale, the most important parameters for unsaturated mass transport analysis of GONPs-reinforced calcium silicate hydrate (CSH) are determined through the molecular dynamic (MD) simulation. At the microscale, a hydrated cement model is adopted and its penetration characteristics are calculated. At the mesoscale, a three-phase mesoscale model of concrete is presented, which considers particles, cement paste, and the interfacial transition zone (ITZ) as separate constituents to simulate the unsaturated flow under the mixed actions of capillary suction, external hydrostatic pressure, and gravity. The proposed approach is validated by comparing the numerical result with those of the available experimental data taken from this paper to verify the reliability and efficiency of the multiscale model for predicting the unsaturated water transport properties. Experimental and numerical results indicate that the incorporation of a very low fraction of GONPs (0.1% by weight of cement) can effectively hinder the ingress of water molecules. It can be concluded that adding GONPs improves the transport properties of concrete which subsequently improves its durability.

کلیدواژه‌ها [English]

  • Graphene oxide nanoparticles (GONPs)
  • Concrete
  • Durability
  • Unsaturated water transport
  • Multiscale approach
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